REU Presentation Archives

Characterizing the Circumstellar Envelope from Asymptotic Giant Branch Star RX Boötis
Juan Cardenas – Cornell University (poster)
We present a detection of the H I 21 cm line associated with the circumstellar envelope (CSE) of the asymptotic giant branch star, RX Boo, based on data from the Karl G. Jansky Very Large Array (JVLA) data. The VLA detected emission from the bow shock and diffuse tail of the CSE at 2.5σ at velocities ranging from -3.45 km s−1 to 3.97 km s−1. The H I emission suggests that there exists a hollow hydrogen shell. Far-ultraviolet data of RX Boo from the GALEX archive has an apparent spatial association with the H I emission. The size of the CSE in radio almost mirrors the UV emission at approximately 0.85 pc and 0.84 pc, respectively. Contamination from an unresolved gas cloud was found along the same frequencies as the CSE. No continuum emission was detected in the H I data including the RX Boo star. The corresponding bow shock and tail features reveals the interaction between the CSE and the interstellar medium. We will explore the implications of the relation between the two tracers and their origins.

Geospace Stormtime Plumes in the Ionosphere Observed by GNSS Systems
Patricia Dzwill – New Jersey Institute of Technology (presentation)
Storm-Enhanced Densities (SED) are disturbances in the plasma of the midlatitude ionosphere that occur during geomagnetic storms, that result in heightened levels of Total Electron Content (TEC) that form a narrow plume structure that stretch sunward and poleward from local afternoon. SED can impact telecommunication, so it is important to understand their morphology. Despite all that is known about individual SED events, many aspects are still a mystery. This study provides an analysis of how SED plumes over the continental United States grow and change throughout a set of ~50 intense storms (Minimum Sym-H index < -100 nT). We used data from the ground based GNSS receiver network on the Madrigal database to identify which storms had an SED plume appear, when the SED started and ended, and over which latitudes it spanned. Then by using Gaussian fittings, we calculated the mean and standard deviation values of peak TEC intensity, plume width, and SED central longitude for each 5-minute interval. We analyzed this data over individual days to see how the SED structure changed over time, season, geomagnetic index, solar activity, and F2 layer peak density (NmF2) from the TEC-based ionospheric data assimilation system (TIDAS) to observe how SED formation is correlated. Our results showed that throughout individual storms, the peak intensity tends to increase first and then decrease as the storm proceeds, the central longitude moves westward, and the width tends to remain the same. We also saw that the NmF2
tends to increase, decrease, and peak at the same times as the peak intensity. Over comparisons of long-term factors of all the storms, we saw correlations between the peak SED intensity and peak magnitude of the geomagnetic indices, as well between the latter and the plume width. These results help to build a general knowledge of SEDs and contribute to a greater understanding of the relationship between SED and the space weather environment.

Developing High-Accuracy Empirical Models of Ionospheric Parameters
Fermin Redondo – Clemson University (presentation)
My work this summer covered the construction and evaluation of an empirical local model for F2 layer electron density (NmF2). The model is a linear combination of several predictors, such as solar flux, geomagnetic activity, seasonal variations, and interaction terms. These predictors are fit to ionosonde data that comes from GIRO and WDC NICT databases. This model was recently updated to use the FISM2 index as a proxy for solar flux, but there were still issues with the solar representation in the model. To improve this, I developed and visualized performance metrics on various model iterations using different wavelength bands of FISM2 with different lags applied as predictors. These metrics evaluated the model’s accuracy, bias, precision, correlation, and forecasting skill. I concluded that our original frequency band of 0-105.05 nm was the most effective. With metrics, I also evaluated the model’s training and test data while briefly running a spectral analysis of residuals. Future work will include further investigation into solar proxies, such as testing different FISM2 bands at different time periods.

Future Plans for Madrigal Database
Katherine Cariglia, University of Massachusetts Lowell (presentation)
The Madrigal database is an invaluable source of geospatial data made by instruments from around the world. Currently, the experiment level and file level
metadata does not include the geographical boundaries for each data set, but will be included in the next release of Madrigal (version 3.3) and is being as added as part of my work. These geographical boundaries, which include minimum and maximum latitude, longitude, and altitude for each data set, as well as an interface to select specific boundaries by experiment, will give users the ability to search for data in a particular location, and has implications for integration with Google Maps data. By overlaying Madrigal data on Google Maps, users can visually find which datasets overlap in space and time. Additional updates to Madrigal include metadata containing the NSF grant number for each experiment, and several new data types: magnetometer, riometer, photometer, and VLF data from the South Pole and McMurdo stations, and new quality flags for the DMSP SSIES-3 F16 satellite data.

GNSS SDR for Geodetic or Geospace Measurement
Anton Voronov, University of Massachusetts Amherst (presentation)
Very Long Baseline Interferometry (VLBI) relies on observing faint radio sources, such as distant quasars, to establish precise baselines and make accurate geodetic measurements. Global Navigation Satellite System (GNSS) signals are emitted by a constellation of satellites and are readily available worldwide by providing a constant and reliable signal to Earth-based receivers. Both of these systems are very precise, but do not share anything in common. This project involves finding and developing tools for facilitating combining both of these measurements together, and provides a validation method for a FPGA implementation of the GNSS software stack. To start, a hardware receiver and a Software Defined Radio (SDR) were connected to a geodetic GNSS antenna using a signal splitter. The hardware receiver and SDR would be configured in a way such that they both were logging raw satellite navigation system data, recording at the same time, to a universal geodetic file format, for comparison. After it was determined that this was functioning, implementing multiple GPS bands was attempted, and the RF data was recorded to be processed at a later time. Additionally, a tool was developed to enable the conversion of data recorded in Haystack’s DigitalRF format to VDIF, a format compatible with the VLBI network.

Developing Software Tools to Monitor Antarctic Ice-Shelf Stability
Aishwarya Chakravarthy, Georgia Institute of Technology (presentation)
Ice shelves play a vital role in preserving the health of the Antarctic cryosphere ecosystem and beyond. By serving as a buttressing force, ice shelves prevent sea
level rise by halting the release of glaciers to sea. Sea level rise harms the global environment in a variety of ways, including flooding habitats, eroding coastlines, and contaminating soil and groundwater. Therefore, it is essential to monitor the health of Antarctic ice shelves, potentially using a variety of data sources: including seismic, geodetic, and weather measurements. We propose RIS-Vis, a novel data visualization procedure to monitor ice shelf health at the Ross Ice Shelf (RIS) in Antarctica. RIS-Vis is capable of generating visualizations of seismic miniSEED data, geodetic RINEX files, and weather-related measurements to provide meaningful results for scientists. RIS-Vis was built using open-source Python libraries including Obspy, APScheduler, and the Plotly Dash framework. Visualizations developed on RIS-Vis include filtered waveforms, spectrograms, power spectral densities, temperature/pressure/humidity plots, as well as ice shelf movement plots. The dashboard visualization platform abstracts away the time-intensive analysis process of raw data, and allows for scientists to easily generate conclusions about RIS health changes over time. The development process used in this study could easily be applied to visualizing data from other fields, demonstrating its relevance as a broader tool for scientific visualizations.

Deformation Analysis for Arctic Sea Ice
Brighten Jiang, University of Florida (presentation)
The Arctic snow layer is important for both the local and global climate. It provides insulation to the underlying sea ice preventing its melt and slowing the rise of sea levels. Current studies of snow depth are limited to expensive or dangerous in-situ measurements or airborne surveys. We examined snow depth in a region of the Beaufort Sea using data from 3 sources: the altimetry missions from ICESat-2 (a lidar) and CryoSat-2 (a radar) in conjunction with MIT SIDEx measurements. The lidar measures the top of the snow layer, while the radar measures the bottom, so differencing their measured heights provides an estimate of the thickness of the snow layer. SIDEx gives timely and accurate measurements of ice drift over time, enabling us to measure the snow depth to greater precision than simply using the two satellites.

LEGO: Using Dark Clouds in the Milky Way to Understand Distant Galaxies
Marissa Perry, The University of Texas at Austin (presentation)
To develop a thorough understanding of the structure and evolution of galaxies, we are required to investigate the fundamental process of molecular cloud
formation. Although galactic molecular clouds have been studied in great detail, spatial resolution of current radio telescopes inhibits our ability to resolve individual molecular clouds in external galaxies. As a consequence, we receive an averaged signal over a range of chemical environments in a number of molecular clouds. Thus, cloud population synthesis techniques are essential to understand the assembly of extragalactic systems. Here we theoretically model the decomposition of an extragalactic luminosity signal into its molecular cloud components, exploring the existence of molecular cloud “categories”. The identification of molecules that can plausibly serve as tracers of physical properties are also explored in depth, as they are key to forming connections between chemical and physical cloud environments.

Using a Natural Cosmic Telescope to Study a Distant Radio Quasar
Sophia D’Agostino Rubens, Dartmouth College (presentation/poster)
This project is aimed at understanding the relationship between the low-energy (radio) and high-energy (γ-ray) emissions from the blazar PKS 1830-211, leveraging its unique gravitational lensing effects. The lensed components, NE and SW, are distinguished by their notable time delay (~26 days) and magnification ratios, making them valuable tools to study the background blazar. Using time-monitoring light curve data and high–angular resolution VLBI radio data observed during an unprecedented γ-ray flaring event, we aim to characterize the physical mechanisms responsible for these phenomena. We have identified γ-ray flaring patterns, some linked to radio activities and others not. Non-associated flares likely result from microlensing, while related ones are due to inverse Compton scattering in the jet. Multi-frequency VLBI images show varying magnification of lensed radio components during these flares, suggesting a chromatic jet structure and evolving jet core emissions, possibly due to the jet core’s opacity effect.

Deuterium Content Towards Galactic Center Molecular Clouds
Nancy Sohlberg, University of Utah (presentation)
Star formation in the Milky Way Galactic Center (GC) is challenging to study because of the extreme environmental conditions present throughout the region. High densities of material at varying levels of turbulence and temperature create a combination of unfamiliar chemistry and hard-to-obtain measurements. One
strategy that has been implemented to probe this region is the detection of deuterium as it is a good tracer of star formation. Successful measurements have
indicated unexpectedly high amounts of deuterium with respect to hydrogen, but the limited number and diversity of such measurements has left a large amount of ambiguity around those results. The following research addresses this deficit and uses observations of deuterated linear molecules and their corresponding
hydrogenated isotopologues from 5 different molecular clouds in the GC to estimate the deuterated molecular abundance ratio in this complex region. Values obtained were consistently on the order of 10-3 which is in agreement with previous work (Colzi et al., 2022; Jacq et al., 1999; Lubowich et al., 2000), and confirms the presence of deuterium fractionation – the enrichment of molecular deuterium – in the GC.

Observing Black Holes with the Event Horizon Telescope
Anna Tartaglia, The Pennsylvania State University (presentation)
The Event Horizon Telescope (EHT) has imaged black holes Messier 87 (M87∗) and Sagittarius A∗ using Very Long Baseline Interferometry (VLBI). Sagittarius A*’s position at the center of the Milky Way poses unique challenges in image reconstruction, as the turbulent Interstellar Medium (ISM) causes long timescale
refractive scintillation of the source radio emission as it passes through. This scintillation manifests as distinctive substructure variations in the black hole image
on the sky. The standard scattering model and mitigation algorithms, implemented in Python’s eht-imaging library, have significant limitations in modeling scattering jointly in the image reconstruction process, due to Python’s computational speed and the absence of efficient auto-differentiations (AD) for complex forward modeling. Here, we explored and developed the implementation of the scattering model in Julia, a modern high-performance computing language, which can potentially cut computation times significantly and offer rich modeling capabilities via efficient AD algorithms. We present 2 new Julia packages:
StationaryRandomFields.jl, which generates correlated power-law noise on N dimensional signal data, and ScatteringOptics.jl, which implements the Stochastic
Optics ISM scattering framework, both intended for EHT usage. We find that ScatteringOptics.jl constructs scattering kernels and calculates visibilities at speeds
up to 100 times faster than its Python counterpart. With this significant speed up, the Julia implementation will allow a joint modeling of scattering parameters and reconstructed images in self-consistent way. Fractional errors between our scattering kernel and eht-imaging’s scattering kernel range on the order of 10−6 and well within the uncertainty limits for 3 different kernel models. Both modules are available in Julia’s central repository.

LEGO: Why is HCN Unexpectedly Bright in Gas of Low Density?
Anna Apilado, Wellesley College (presentation)
To resolve the challenges that current observational constraints pose in star formation research, the Line Emission as a Tool for Galaxy Observations (LEGO) project utilizes molecular line emissions to map out molecular distributions within clouds in the Milky Way. As part of furthering the current understanding on star formation, assumptions made about star formation need to be verified. It is a general assumption that 1) star formation rate ˙M⋆ is proportional to mass of dense gas Mdg and 2) star formation rate is proportional to luminosity in infrared LIR. When explored whether these assumptions held true, Gao & Solomon reasoned that Mdg is proportional to infrared luminosity of HCN LHCN due to HCN’s high critical density with the common assumption that densities ≫ 104cm−3 are needed to excite HCN. However, the LEGO Survey found that HCN traces densities one to two orders of magnitude less than what Gao & Solomon estimated. This poses the question of why HCN is unexpectedly bright in gas of low density. Possible explanations for this include a higher HCN abundance than expected or an excitation is stronger than predicted. To probe this question, we applied a non-LTE radiative transfer software to measure column density of HCN (J=1-0), corresponded it with the observed brightness temperature from the LEGO survey, and calculated HCN abundance (NHCN/NH2). Input parameters of the software, particularly line width, column density, kinetic gas temperature, and gas density were explored in depth in addition to this calculation.

Automated Detection System for Gravity Waves on Antarctic Ice Shelves Using Supervised Panoptic Spectrogram Segmentation
Shivansh Baveja, University of California, Berkeley (poster)
The ice shelves fringing the Antarctic continent play a pivotal role in stabilizing the Antarctic Ice Sheet by restraining, buttressing, and modulating the flow of grounded ice into the Southern Ocean. Recent ice shelf collapses suggest that low-frequency (0-70 mHz) gravity wave forcings may trigger rapid shelf disintegration. This study focuses on applying machine learning to automatically detect, classify, and catalog low-frequency gravity wave events impacting the Ross Ice Shelf (RIS) with panoptic seismic spectrogram segmentation. The data used to supervise training were collected by a broadband seismic array deployed on the RIS from November 2014 to November 2016. Our modified U-Net architecture achieved a Dice similarity coefficient (DSC) of over 0.73 during event detection and an accuracy of 94.4% during classification, outperforming alternative rule-based techniques. This work serves as a proof-of-concept for using deep-learning algorithms to detect and catalog gravity wave events, enabling further analysis into the long-term stability of Antarctic ice shelves.

Removing Radio Frequency Interference from Auroral Kilometric Radiation with Stacked Convolutional Denoising Autoencoders
Allen Chang, University of Southern California (presentation)
The AERO/VISTA missions are twin 6U CubeSat missions that will investigate Auroral Kilometric Radiation (AKR), the strongest of many types of radio emission that originate from energetic electrons in the Earth’s auroral zones. AKR data, typically visualized as time-frequency spectrograms, can be corrupted by noise from nearby electronics and power systems, AM stations, and geo-stationary satellites, limiting the ability to analyze AKR observations. Thus, image processing methods that can reconstruct detail from noisy or occluded observations are a critical pre-processing stage to improve downstream analysis of AKR. We present the Denoising Autoencoder for Auroral Radio Emissions (DAARE), which leverages stacked autoencoders trained with synthetic spectrograms to remove Radio Frequency Interference (RFI) from AKR spectrograms collected at the South Pole Station. We compare DAARE across filtering and deep-learning denoising algorithms with Peak Signal-to-Noise Ratio (PSNR) and Structural SIMilarity (SSIM) evaluations. DAARE achieves 0.422 PSNR and 0.981 SSIM scores on
synthesized AKR observations, improving PSNR by 0.039 and SSIM by 0.064 compared to baseline methods. Removing RFI from AKR observations could assist space scientists in identifying AKR and other auroral emissions from the AERO/VISTA missions. The framework for simulating AKR, training DAARE, and using DAARE can be accessed at https://github.com/Cylumn/daare.

Observing Black Holes with the Event Horizon Telescope
Katy Hunter, University of Michigan (presentation)
Context Using very-long baseline interferometry (VLBI), the shadow of the M87 supermassive black
hole has been imaged by the Event Horizon Telescope (EHT). M87 is predicted to also feature an unstable circular orbit of light called the photon ring outside of this shadow and an inner ring structure created by a relativistic jet expelling ionized matter. While the shadow and outer ring are shifted as the spin of a black hole increases due to gravitational lensing and rotational frame-dragging, the position of this inner ring is not affected by the black hole’s spin.
Aims By measuring the offset between the positions of the inner and outer rings, the spin of M87 can be measured.
Methods This paper simulates observations to test whether the inner and outer rings can be detected at 290 GHz and 345 GHz with the EHT and various ground and space elements, using both SMILI and EHT-imaging techniques. In addition, Variational Image Domain Analysis (VIDA) and Comrade modeling were tested in order to determine whether the offset between the inner and outer ring could be quantified with feature extraction.
Results After determining that the maximum baseline limits of ground VLBI make imaging and modeling the rings impossible from only ground-based telescope arrays, space-based telescope arrays with multiple geosynchronous (GEO) satellites or a single medium-earth orbit (MEO) satellite produced images and models with both rings visible. The offsets per spin were plotted against predicted values for various telescope arrays and modeling methods, and a promising correlation was demonstrated.
Conclusions Although additional iterations need to be performed to verify these results, our experiments support the need, viability, and importance of incorporating GEO or MEO satellites into the EHT array in order to study the structures and spin of M87.

AERO-VISTA Satellites
Alexis Lupo, The University of Texas at El Paso (presentation)
Auroral Emission Radio Observer (AERO) and Vector Interferometry Space Technology using AERO (VISTA) are twin CubeSats that will study auroral radio emissions in the ionosphere near the Earth’s poles from low-Earth orbit. The Earth’s auroral regions contain a space plasma that will strongly affect the impedance of the vector sensor (VS) antenna, causing a change in sensitivity. This project seeks to explore this effect by first calculating the plasma impedance and then modeling its impact on the sensitivity along the spacecraft’s orbit. We then use this improved sensitivity within AERO-VISTA’s larger simulation framework to create synthetic data that is representative of a data collect during the AERO-VISTA mission. The framework developed for this project can be used in operations tests as well as the development of algorithms to measure in-situ plasma parameters.

The Great Haystack RFI Hunt
Brian Malkan, Case Western Reserve University (presentation)
My project aims at detecting sources of Radio Frequency Interference (RFI) across various frequency ranges. I worked with my mentors Dr. Frank Lind and Dr. Sharanya Srinivas towards the ultimate goal in creating training data for machine learning. To detect RFI I created a python script using GNU-Radio, Python and DigitalRF. The script worked in tangent with my “shoebox device”, which is a portable machine I could carry around the observatory to detect RFI from different sources. Once the data was collected, I fed into a data visualization app, made using Dash and Python. From here I was able to annotate specific peaks and discrepancies, and create some example training data.

Simulation of Radar Meteor Ground Illumination to Optimize the Configuration of the Zephyr Meteor Radar Network
Kathryn Postiglione, Princeton University (poster)
Since meteors occur randomly within the sky, it is crucial to deploy meteor radar networks that maximize the ability to observe meteors and derive upper-atmospheric winds. To accomplish this task, we developed a meteor simulation model in Python to calculate received power as a function of location given transmitter and meteor properties. An interactive and real-time updating meteor simulation map was created to fully understand each simulated meteor. This map displays received power for specified longitude and latitude ranges. Adjusting the meteor, transmitter, and receiver variables allows the user to identify trends and find optimal transmitter and receiver locations. Since there are an unlimited number of unique meteors, simulations were run to create thousands of distinct meteors for each receiver location within specified longitude and latitude ranges. A special focus was placed on finding an ideal location in Colorado for the Zephyr Meteor Radar Network’s transmitters and receivers, so all simulations were based on longitudes and latitudes within Colorado. Ultimately, the improved placement of transmitters and receivers will result in increased sky coverage of potential meteors and their specular trails, which act as natural tracers of upper-atmospheric winds.

VLA Observation of Teegarden’s Stars
Angelu Ramos, University of Hawaii Hilo (poster)
We investigate Teegarden’s Star (also known as GAT 1370, SO J025300.5+165258) for radio emissions caused by magnetic interactions between the star and its planet. This is 1 of 5 stars to
be investigated in a survey that consists of nearby stars that are < 5 pc away. Teegarden’s star is a late M dwarf suspected of being a young star with a planet that is thought to be ~4.88 MNEP with a ~2 day orbit (a = 0.0014 AU). Being an M dwarf star, it has a strong magnetic field but the magnetic field of its suspected planet is unknown which is where radio observations come into play. Planetary radio emissions will be evident through excited charged particles in the planet’s atmosphere, and/or planetary magnetic field interactions with solar wind. Observational data from the VLA in the P Band (0.23 – 0.47 GHz; 90 cm) and Teegarden’s star strong magnetic field allows for reasonable ground based survey. The VLA observed Teegarden’s star on August 16, 2016 within the times of 11:31:50 to 12:11:40 (~40 minutes) on the same day. With NRAO’s Common Astronomy Software Applications (CASA), we are able to calibrate and image the P Band data – imaging is taken a step further by imaging between the different spectral windows and then by time frames. In our process, we did not find any radio emissions from Teegarden’s star but have established an upper limit on P-band radio flux from this system.

AERO-VISTA Satellites
Max Riccioli, University of Texas at Austin (presentation)
The AERO-VISTA mission will study auroral radio emissions and demonstrate interferometry using electromagnetic vector sensors from low earth orbit through eponymous twin 6U cubesats Auroral Emission Radio Observer (AERO) and Vector Interferometry Space Technology using AERO (VISTA). As part of this mission, a reliable and extendable software package has been developed to facilitate communication between the satellites and ground stations. This project has added critical improvements to the core ground station software: the ground station interface is now capable of managing several GNURadio flowgraphs concurrently, as well as loading arbitrary flowgraphs from file; configuration options have been extended for many components of the ground system; mission-specific definitions, routines, and flowgraphs have been reorganized and consolidated into a central package. Additionally, numerous flowgraph-level enhancements have been made: defective packets can be detected in-flowgraph, preventing packet drops due to apparent overlap; improved demodulation and signal processing methods reduce GFSK bit-data quantization errors; and data pre- and post-processing methods reliably discern packet transmissions from radio noise. Finally, the ground station interface’s existing Redis server integration has been leveraged to send uplink and downlink entries across NNG pipes, allowing for eventual connection to NanoMCS for complete data packetization and depacketization as will be seen during actual mission operation. Before the package is mission-ready, further integration with other mission-level software is still necessary, as are more robust signal processing options. With the above improvements, however, a flexible framework has been created to allow for quick development of these features.

Resolving the Motion of the Accretion Flow and Jet of M87*
Audrija Sarkar, Northeastern University (presentation)
The Event Horizon Telescope (EHT) currently produces static images of the emission surrounding supermassive black holes. A key goal over the next few years is to lengthen the observing window in order to produce videos of the supermassive black hole at the center of Messier 87, M87*. An important purpose of such a video would be to resolve the complex dynamics of material in the accretion flow and jet. In this project, we have developed a tool to extract and characterize motions. For the motion extractions, two methods were examined using videos generated from general relativistic magnetohydrodynamic (GRMHD) simulations: voxelmorph, a neural network used in medical imaging, and Lucas-Kanade method in opencv, a classical technique to measure the dense optical flow. We find that the Lucas-Kanade method is more effective at detecting spiral motion than voxelmorph. We further characterized the extracted angles of rotation and velocity field with polar Fourier analysis. These results demonstrate that optical flow methods may be used to characterize the dynamics of the accretion flow and jet from EHT observation.

Statistical Studies of Traveling Ionospheric Disturbances and Equatorial Plasma Irregularities
Tal Sternberg, Dartmouth College (poster)
Traveling ionospheric disturbances (TIDs) occur as a result of space and terrestrial weather. Some previous case studies have suggested TIDs are likely associated with the presence of equatorial plasma irregularities (EPIs). This study provides statistical analysis of both TIDs and EPIs in the America sector as well as their potential correlation. The GNSS measurement of total electron content (TEC) from ground-based receiver networks can be used to identify potential TIDs. A large global TID dataset based on ∼6000 GNSS receivers is being created at MIT Haystack Observatory for every day since 2018 using a previously developed TID detection algorithm where a 30-min sliding widow is used to detrend background ionospheric variations. Monthly averages of TID amplitudes with up to 1 deg latitude by 1 deg longitude by 5 min time interval spatial-temporal resolution, are calculated. These allow us to examine the TID climatology on local, regional, and global scales. We have developed various visualization tools to assist in the characterization of TID climatology including day-to-day, seasonal, and long-term variations. Equatorial Plasma Irregularities (EPIs) are normally considered to be developed under the Rayleigh-Taylor instability where the seeding effect of neutral and ionospheric waves is important. To characterize EPIs, we use the GOLD’s nightglow measurements at 135.6 nm. A statistical analysis for the EPI occurrence in the GOLD data is performed over the years since 2018, corresponding to the period when the GNSS TID climatology is derived. In this presentation, we will report climatological results from both TID and EPI statistical studies, and explore the potential connection of EPI development to TIDs.

Sensing Snow Depth over Arctic Sea Ice Using GPS Reflectometry
Sarah Zhang, University of California, Berkeley (poster)
The thermal insulating properties of snow are quite extraordinary. In the Arctic Ocean, processes, such as sea ice formation and melt, are partly regulated by the thickness of the snow layer that overlies the sea ice. It is therefore important to obtain reliable estimates of snow depth over sea ice to understand ongoing changes in Arctic Ocean sea ice cover. Here, we explore the feasibility of snow depth estimation using the Global Navigation Satellite System-Interferometric Reflectometry (GNSS-IR) technique. This remote sensing technique uses the interferometric pattern in the GNSS Signal-to-Noise Ratio (SNR) observable, which results from the interference of the direct and reflected GNSS signal, to estimate the vertical distance between the receiving GNSS antenna and the reflecting surface. In the case of Arctic sea ice, the reflector is the snow, and vertical distance changes are due to snow accumulation or melt. The cm-level precision of the GNSS-IR technique has previously been demonstrated using stationary GNSS antennas. Here, data from the Sea Ice Dynamic Experiment (SIDEx) is used to investigate the precision of kinematic GNSS: GNSS antennas are anchored to an ice floe, drifting with the Arctic Ocean ice pack. We have processed approximately one month of GNSS data from 12 identical GNSS systems deployed during the March 2021 SIDEx campaign, forming a small-scale network of ~5 km. There are noticeable differences between systems, possibly attributed to the quality of the reflecting environment. Overall, the cm-level precision of GNSS height estimates in this kinematic environment demonstrates consistency with the precision of estimates from static GNSS-IR studies. These are promising results for validating the most recent estimates of snow depths from remote sensing missions, such as ICESat-2 and CryoSat-2.

AERO-VISTA
Lucas Briggs, Northeastern University (presentation)
AERO and VISTA are twin 6U small satellite missions funded through NASA and are both being led by MIT Haystack Observatory. The main goal of the missions is to study the radio emissions from the aurora and will require the downlink of numerous types of data. As part of these missions a testable digital radio interface for CubeSat communications has been developed. This radio interface is designed for maximum flexibility and versatility using open-source software tools. The signal chains for both transmitter and receiver allow reliable “bursty” transmission of definite-length packets using GFSK modulation/demodulation between two USRP B210 SDRs using GNURadio. Packet input/output utilizes ZMQ message-passing blocks such that packets can be built/parsed using more straightforward Python class implementations. Radio and packet building parameters are fully configurable through YAML files. These parameters include center frequency, samples per symbol for GFSK, packet length, syncword, CRC, and whitening. A REDIS database is used to stream data to and from the radio communication interface. Other entities within a larger satellite ground data pipeline can connect to this REDIS database as an API in order to, completely asynchronously, schedule packets for uplink or read packets received at downlink. All software is designed with proper SOLID principles and object composition/inheritance patterns in mind to create a package that is as configurable and extendable as possible.

Sensing snow depth over the Arctic sea ice using GPS reflectometry
Tyler Landsparger, Pennsylvania State University (presentation)
Over the past two decades, researchers have used the Global Positioning System Interferometric Reflectometry (GPS-IR) remote sensing method to detect soil moisture content, low-lying vegetation, tidal heights, and snow depths remotely. This method involves comparing the strength of a GPS signal hitting a fixed GPS receiver directly to that of a reflected signal of opposite polarity hitting the same receiver. Prior to our investigation, the scientific community had yet to attempt remote sensing using GPS-IR with a GPS receiver site that is not stationary relative to the Earth’s surface. With the vision of providing climate models with current, accurate Arctic snow depth data via remote sensing, we planted a cluster of GPS receivers on sea ice drifting in the Beaufort Sea to sense the snow depths there over time.
In order to extract the direct-versus-reflected signal data, or the Signal-to-Noise Ratio (SNR), we downloaded and installed a software package called “gnssrefl” and advanced its data analysis capabilities using code of our own. We first tested this software by extracting SNR data from two stationary GPS sites. These tests reproduced previous researchers’ successes in remotely sensing snow depths and tidal heights using the GPS-IR method. Having validated GPS-IR as an effective remote sensing method, we then entrusted the method and the software with our drifting GPS receivers in the Arctic. Upon processing the first three days of SNR data recorded at two of our Arctic GPS sites, we were surprised to find that their westward acceleration had little to no impact on the SNR or reflector height results. Both sites moved about 2 meters on the first day, versus 200 meters on the second day and almost 40 kilometers on the third day, yet only minute variations in the data were observed between these days.
Due to the small sample size analyzed thus far, further investigation is required before any definitive conclusions can be drawn. However, the initial GPS-IR results from our Arctic sites are encouraging.

Climatology of Thermospheric Neutral Winds over Millstone Hill
Emily McMinn, Valparaiso University (presentation)
Millstone Hill’s Fabry-Perot Interferometer (FPI) has historically been used to measure the 630.0-nm nightglow emission at an altitude of ~250km. Millstone Hill’s FPI has been in use since 1989 but went offline briefly from 2003-2008 to receive high-resolution upgrades. Previous studies have used this database to analyze the climatology and latitudinal gradients of quiet time thermospheric neutral winds. Since 2009, the FPI has been collecting zonal and meridional thermospheric wind data; however, it has not been explored nearly as in-depth as the historical database has been. The Millstone Hill incoherent scatter radar (ISR) geospace facility offers both a steerable (MISA) and fixed (Zenith) antenna which provide complete profiles of electrons and ions (temperature, density, and velocity) within the ionosphere. This project aims to collectively use both of Millstone Hill’s new ISR and FPI databases to investigate the thermospheric zonal and meridional neutral wind climatology and response to subauroral polarization stream during geomagnetic storm and substorm periods. We attempt to create a seasonal climatology for quiet- and active time neutral winds by averaging the monthly neutral winds and plotting 2-dimensional temporal distributions for low and high solar activity periods. We also examine the specific differences between the winter and summer neutral winds; however, our focus is analyzing the differences in the thermospheric neutral wind during the spring and autumnal equinoxes.

Studying auroras with total election content (TEC)
Conrad Meyer-Reed, University of Colorado Boulder (presentation)
Observations of correlations between Total Electron Content (TEC) gradients in the ionosphere and GNSS signal phase scintillation have provided essential information about near-Earth space weather phenomena, illuminating fundamental processes of magnetosphere-ionosphere (M-I) coupling. TEC data are provided by the world-wide network of GNSS receivers, and amplitude and phase scintillation parameters are provided by specialized GNSS receivers from the NSF MRI Collaborative: Development of Monitors for Alaskan and Canadian Auroral Weather in Space (MACAWS) and the Canadian High Arctic Scintillation Network (CHAIN). All of this data is available in NSF’s CEDAR Madrigal database. For high latitudes, the phase scintillation is more significant, and this is the parameter we report on in this study. We will detail the development of a software package with functionality allowing an analysis of All-Sky Imager (ASI) auroral images from the THEMIS database at University of Calgary and from additional imagers at the University of Alaska combined with the scintillation parameters and TEC data sets described above. By merging THEMIS auroral images, binned TEC, and scintillation events then mapping these data sets onto geographic coordinates, we monitor the relationship of GNSS scintillation with the intensification of auroral activity across Canada and Alaska. Further analysis of magnetometers can be used to monitor the onset of geomagnetic storms and substorms. To demonstrate the functionality of this software package, a case study geomagnetic storm from 2020 will be studied. By using data from the THEMIS All-Sky Imager network during times corresponding to substorm activity, correlations between phase scintillation occurrence, TEC gradients, and auroral activity can be observed. We will conclude with a few illustrative examples.

Measuring meteors and estimating winds with the Zephyr meteor radar network
Oana Mirestean, Cornell University (presentation)
Neutral atmospheric winds in the mesosphere and lower thermosphere (MLT) region cannot be directly measured and, instead, are estimated using meteor radars that detect meteor trail echoes in this region. Gaussian process regression (GPR) has emerged as a viable approach to estimate the wind velocity components for the zonal, meridional, and vertical directions as a function of 3-D space and time. The method takes prior wind distributions (specified as a set of mean and covariance parameters) and measured wind velocity projections as inputs and yields a posterior distribution for the wind velocities. Running a GPR depends fully on computations using the mean and covariance function matrices. The computational complexity of performing matrix operations on the 𝑛𝑛 × 𝑛𝑛 covariance matrix (the data set has 𝑛𝑛 measured wind observations) for the GPR is 𝒪𝒪(𝑛𝑛!). The high computational power demanded by this approach restricts the amount of data processed by the method at once and leads to high computational time. Previous models were only able to use data corresponding to 90-minute observation batches (a maximum of ~13,000 measurements). We aim to improve the computational efficiency of estimating the upper atmospheric winds by using GPyTorch, a Python library for GPRs based on the machine learning library PyTorch. Using this approach, we were able to dramatically improve the computation time while maintaining the accuracy of the previous model. Future work will leverage the reduced complexity to perform computations on much larger datasets.

AERO-VISTA
Aparna Rajesh, Stevens Institute of Technology (presentation)
The AERO-VISTA (Auroral Emission Radio Observer – Vector Interferometry Space Technology using AERO) is a twin-satellite CubeSat Launch Initiative mission that is tasked with analyzing the Earth’s auroral emissions at radio frequencies. Using vector sensors, the two satellites will observe auroral roar, auroral hiss, medium frequency burst, and auroral kilometric radiation. The Command Schedule Application Programming Interface (AV-Command-Schedule-API) was developed as an intermediary satellite commanding-pertinent software for this mission. The API serializes satellite command information using payload data, static command data, command metadata, and spacecraft configuration information, and the API packages it into two formats: a human-readable String format and a hex string that will be processed by the spacecraft. This API lays the groundwork for an object-oriented process of generating commands. Its repository can be accessed at: https://github-mit-edu.ezproxy.canberra.edu.au/AEROVISTA/AV-Command-Schedule-API

AERO-VISTA
Hirani Sattenapalli, Carnegie Mellon University (presentation)
The AERO-VISTA satellite missions are set to launch in 2022. AERO (Auroral Emissions Radio Observer) and VISTA (Vector Interferometry Space Technology using AERO), 3U size CubeSats meant for a low earth polar orbit, will collect radio emission data from the auroral regions at high (100 kHz – 5 MHz) and low frequencies. Using Vector Sensor Interferometry, AERO and VISTA will collect angle of arrival, polarization information, and samples of amplitude and phase of the electric and magnetic components of the waves. This information is then used to classify auroral emissions (AKR, MFB, Hiss) and provide scientific data for understanding propagation mechanisms of AKR, characteristics of Hiss and MFB, and other larger scientific goals. Observations and analysis of radio emissions from the auroras can provide ways to remotely sense auroral ionospheric plasma conditions and detect and predict space weather conditions. The AVIS (AERO-VISTA interactive spectrogram) display will provide a tool for the science team to visualize downlinked data, process and perform computation on spectrogram data which can be used for uplink back to the spacecraft, and visualize telemetry data of the spacecrafts. This summer, the AVIS dashboard, originally created in summer 2020, was extended, with new graphics to display both AERO and VISTA spectrograms, a page to display telemetry data (spacecraft location, speed, altitude), and generation of spectrogram subplots to perform computations. Partially ready for use, improvements, including increasing the speed of spectrogram plot generation, completing software for internal computation, and increasing the efficiency of data organization, can allow the dashboard to be ready for use by the Science team.

Development of a seismo-geodetic software package for Antarctic glaciology
Linnea Wolniewicz, University of Colorado, Boulder (presentation)
Antarctic ice shelves buttress glaciers on land and restrain ice from sliding into the ocean. Due to climate change the ocean and atmosphere surrounding these ice shelves has warmed and as a consequence they are less stable and more susceptible to ocean forcing. Seismic stations positioned on the Ross Ice Shelf (RIS) have monitored the motion of the ice shelf with respect to ocean forcing events, which induce flexural-gravity and lamb waves in the ice shelves. These waves can trigger calving events and ice shelf collapse. Detecting these wave events is important to understanding ice shelf stability, however only a few events have been documented in the literature. In this REU project I have developed a software package which can automatically detect wave events in seismic data collected on the RIS in Antarctica. I apply a Gaussian Mixture Model (GMM) which clusters seismic spectrograms to detect high-power wave events. I also use OpenCV’s fit Ellipse function to identify dispersive wave signals in the clustered spectrograms. This software package can be applied to future seismic data to create a labelled dataset for training a Convolutional Neural Network (CNN) to classify wave events impacting the RIS.

Three-dimensional ionosphere and sensor modeling with GEMINI
Isaac Wright, The University of Texas at Dallas (presentation)
GEMINI (Geospace Environment Model of Ion-Neutral Interactions) is a three-dimensional ionospheric multifluid-electrodynamic model. The ionosphere is a region of Earth’s atmosphere (~80-1000km altitude) characterized by a large density of free ions and electrons due, in part to, solar photoionization. GEMINI has been used to model transient phenomena including the effects of natural hazard events on the ionosphere, auroral currents, and radio wave fluctuations resulting from ionospheric instabilities. Here we present our efforts toward three major goals: (1) to setup capabilities for Haystack scientists to use and run GEMINI, (2) to explore the model’s capacity in producing various physical features, and (3) to model the June 2021 annular eclipse as a case study illustrating GEMINI capabilities. Throughout this project, we have succeeded in setting up and operating GEMINI on MIT Supercloud, a high-performance cluster computing environment available to MIT students & staff. We have confirmed general physical consistencies in producing features such as the Equatorial Ionization Anomaly and day-night ionospheric parameter variations. Additionally, we have demonstrated via our case study of the June 2021 annular eclipse the capability for GEMINI to reasonably modulate photoionization.

The Polar Vortex’s Effects on TIDs
Izzi Ariail, University of Oklahoma (Presentation)
The stratospheric polar vortex encompassed by the westerly jet stream in the Northern hemisphere is subject to weakening and strengthening, sometimes at a rapid pace. Rossby waves formed in the troposphere can propagate upwards and disrupt the jet stream, leading to sudden stratospheric warming events (cite). These disturbances to the polar vortex create gravity waves that are capable of traveling well into the ionosphere. This study is focused on whether these gravity waves are capable of disrupting the total electron content (TEC) enough to produce traveling ionospheric disturbances. In this project we examine the total electron content over the U.S. and western Europe at 60 degrees latitude to determine what regional and temporal patterns exist. While taking into consideration geomagnetic and solar effects, we then look at whether or not gravity waves caused by the polar vortex could initiate TIDs. Compared to Europe, the U.S. exhibited much higher differential total electron content values across all levels of TEC, kp, and f10.7, indicating that regional differences may depend more on magnetic latitude and gravity waves than background TEC and geomagnetic activity.

LEGO: Using Dark Clouds in the Milky Way to Understand Distant Galaxies
Amanda Broadmeadow, University of Rochester (Presentation)
Extragalactic star formation research often has to make substantial assumptions, since star–forming sites in galaxies cannot be resolved well. To give an example, research often presumes that the mass of dense gas, M_dg , is proportional to the luminosity of the HCN emission, L_HCN. This can then, e.g., be used to study whether the star formation rate, Ṁ_★, is proportional to the mass of dense gas. A direct correlation between L_HCN, M_dg, and Ṁ_★ is, for example, generally assumed to explain the so–called Gao & Solomon relation, i.e. Ṁ_★ ∝ L_HCN for entire galaxies, and today this explanation forms the foundation for much of our understanding of how stars and galaxies formed over cosmic time. The exact relationship between, e.g., dense gas and line emission has, however, never been studied in detail in the Milky Way.

The LEGO survey was therefore created with the goal of examining how line properties connect to physical properties of gas in molecular clouds. To do this the LEGO survey collects data on various molecular clouds within the Milky Way. This data is stored in a three-dimensional data cube with axes of right ascension, declination, and velocity. In order to properly visualize the emission data, these cubes need to be processed into two-dimensional maps. This project discusses the preparations for choosing reobservation targets for the 2020 summer observing run through data quality checks. Also discussed is the methods used to collect our observational data using the IRAM 30m telescope. Finally, this project will explain the development of a data processing code which can produce various 2-D maps of targets. This code can be used to develop the necessary maps for data analysis as well as efficiently check the quality of our observations. Following the completion of this pipeline, the code was used to develop maps to begin an analysis of G11.11-0.12.

Seismo-geodetic Data Processing for Cryospheric Applications in the Arctic and the Antarctic
Emma Chickles, Wellesley College (Presentation)
The ice shelves buttressing Antarctica are important to the stability of the ice sheet covering the Antarctic continent. However, these ice shelves are exposed to the warming ocean from below as well as the rising temperature of the atmosphere. Furthermore, since surrounding small glaciers are melting, ice shelves are also impacted more frequently by ocean waves. This additional forcing by ocean waves can trigger ice calving events or widen existing crevasses in the ice shelf. The SeismoGeodetic Ice Penetrator (SGIP) instrument, which will be deployed in 2021-2022, will monitor the stability of the Ross Ice Shelf and observe the response of the ice shelf to ocean forcing events, such as infragravity waves. This instrument will contain a science-grade broadband seismometer and a high-precision Global Positioning System (GPS) receiver. While the seismometer is sensitive to high-frequency signals, unphysical drifts are introduced when integrating for displacements from seismic data. In contrast, GPS can accurately measure displacements with a very low sampling rate. In this REU project, I developed software using the Kalman filter combination approach to fuse data from co-located seismometers and GPS receivers to obtain more accurate displacements and velocities. The software has been validated by comparing the Kalman filter estimates to the results of Shu et al., (2018), using the same GPS and accelerometer data for the 2016 Kaikōura earthquake. These displacements and velocities will be used to understand the mechanisms contributing to the melting and collapsing of Antarctic ice shelves.

Small Radio Telescope 2020
Blaine Huey, Rensselaer Polytechnic Institute (Presentation)
The Small Radio Telescope (SRT) is an education-oriented radio telescope developed by Haystack Observatory, which, since its inception in 1998, has progressed through many upgrades, taking advantage of the new technologies that have matured in recent years. Since the code for operating the SRT was first written, there have been many advancements and changes in methodology in the world of software development. While the original had custom implementations of every aspect of communicating with motors, tracking celestial objects, signal processing, and displaying those results to the user, incorporating modern libraries could serve to vastly simplify the code and improve the robustness of SRT. Herein we describe the design process, features and operations, and validating experiments on a complete rewrite of the SRT control code in Python, aimed at making its usage by wide audiences easier in a way not previously possible.

MOXIE
Gavin Kohn, University of Maryland (Presentation)
Future Mars missions may use In Situ Resource Utilization (ISRU) technology to provide fuel, oxidizer, and other useful products. The Mars Oxygen ISRU Experiment (MOXIE), a payload on the NASA Mars 2020 mission’s Perseverance rover, will electrolyze atmospheric carbon dioxide, to produce oxygen with carbon monoxide as a byproduct. The Martian atmosphere also contains dust that will collect on MOXIE’s High Efficiency Particulate Air (HEPA) filter. The collected dust will increase the pressure drop across the filter, and may eventually clog it. Therefore, it is important to understand the rate at which dust will be collected. In this paper, the dependence of dust impact rate and dust impact fraction on filter inlet flow speed and horizontal wind speed was investigated using an analytical model and numerical CFD simulation. The analytical model suggested that wind speed up to 10 m/s reduces dust impact rate up to 5%, while the CFD model suggested that wind speed at 10 m/s reduces dust impact rate by about 60%. Both models suggested a linear increase in dust impact rate as filter inlet flow speed increases.

AERO-VISTA Interactive Spectrogram Display
Andrew Langford, University of Notre Dame (Presentation)
The AERO and VISTA 6U CubeSats launching in early 2021 will accumulate terabytes of data a day while observing the auroral regions of the Earth in the radio frequency. With a limited number of downlink opportunities and data rates on the order of gigabytes, mission operations require a tool to most efficiently utilize in-flight processing. The AERO-VISTA Interactive Spectrogram (AVIS) display aims to fulfill this requirement in three ways. The first is to provide spectrogram plots of a large number of summary data files downlinked from spacecraft. Secondly, the dynamic spectrogram display provides enhanced views of the data aiding in event identification. Finally, the AVIS display provides an interactive selection tool to designate bounds for further in-flight processing. Further work on AVIS is aimed at reducing the required user input by training neural networks in the event identification and selection processes.

AERO-VISTA Satellite Dashboard
Emily Mattle, Morehead State University (Presentation)
Auroral Emission Radio Observer (AERO) and Vector Interferometry Space Technology using AERO (VISTA), are a set of identical CubeSats that comprise the AERO-VISTA mission that target analyzing the Earth’s auroral emissions at radio frequencies. The four main types of radio source emissions are auroral roar, auroral hiss, medium frequency burst, and auroral kilometric radiation. AERO-Vista will be measuring the direction of arrival, radio frequency occurrence rates and the frequency spectra for the aurora during its mission lifetime. This set of twin satellites will utilize vector sensors to make these observations. These satellites will orbit in a polar, low earth orbit (LEO). There will be at least four operational ground stations for the duration of the mission after launch. In order to coordinate and organize tracking efforts, a satellite dashboard is being created to interface with ground stations and, subsequently, the ground station operators. This satellite dashboard will be comprised of several components including, but not limited to, a real time map of satellite positions, interactive scheduler, ground station control, and operator communication. For the scope of Summer 2020, the real time map has begun development. Once the entirety of the dashboard is created, it will be robust enough to be utilized beyond the scope of the AERO-VISTA mission in multiple ground stations.

A Multifrequency Collimation Profile Analysis of the 3C279 Jet
Christopher Nadeau, University of Rhode Island (Presentation)
Astrophysical jets emanating from astronomical objects at the center of active galactic nuclei (AGN) are some of the brightest objects in the universe. Despite their status as one of the most energetic phenomena, the process by which these plasma jets are released from the core and the structure of this collimation is still unknown. While lower-luminosity AGN (LLAGN) such as M87 have well-studied collimation profiles, the structure of quasar jets such as the one associated with 3C279 are much less understood despite their relatively higher energy due to the proportionally greater distances that quasars are typically observed at. Here, we present a multifrequency analysis of the archetypal quasar 3C279 in the submilliarcsecond to milliarcsecond scales was conducted using data taken by GMVA including ALMA, VLBA, and space VLBI observations with RadioAstron project over a frequency range of 22 – 86 GHz. The greater angular resolution provided by both RadioAstron and GMVA including ALMA allowed for better resolution of jet structure, revealing a parabolic shape to the submilliarcsecond scale of the jet. This suggests that the jet collimation occurs on the scales of 2 105 4 106 Schwarzchild radii (Rs) from the central engine, in contrast to M87, where collimation occurs up to 105 Rs, while jet width is consistent across both sources. These conditions imply the presence of dense, confining material existing at quasar’s nuclei on much larger scales than LLAGN, which generally exert a sphere of gravitational distance of radius 105Rs.

Multi-scale Imaging for the Event Horizon Telescope
Emmanuel Ogunde, MIT (Presentation)
The Event Horizon Telescope (EHT) has recently provided the first horizon scale images of a black hole opening a new era of black hole astrophysics. The EHT will be expanded to enable it to capture finer scale and more extended emission to further our understanding of black holes. However, as the EHT is now, the single scale reconstruction it utilizes cannot effectively handle the complex multi- scale features to the black hole leading to a loss of detail in these fine details such as the arms of the photon ring. A potential solution of this problem is to use wavelet transformation, a mathematical tool for decomposing natural images into multi-sparse elements. In this REU project we developed a multi-scale imaging technique for radio interferometry by enforcing the condition of sparseness in the wavelet domain. We investigated if the wavelet does this successfully by first testing it with simple denoising to make sure the astronomical images were sparse in the wave domain. Then extending the algorithm to radio interferometric data, we applied it to simulated observations of general relativistic magnetohydronamic (GRMHD) simulations for M87 with the planned EHT2025 array. We found the new technique reconstructs the photon ring, spiral arms and the extended jet structures with a high dynamic range of 1000. The results indicate that this is a viable method worthy of further investigation and development to improve the sophistication of the technique.

Observing Black Holes with the Event Horizon Telescope
Catherine Petretti, Villanova University (Presentation)
The Event Horizon Telescope (EHT), composed of many sub-millimeter radio telescopes across the globe, uses Very-Long-Baseline Interferometry (VLBI) to act as a telescope the size of the Earth. In 2019, the EHT released the first image of a black hole, the supermassive black hole at the center of M87. Such images have the potential to provide insight on highly distorted areas of space-time, the perfect environment to test General Relativity (GR) and to study the astrophysics of jet formation. However, the EHT’s angular resolution of ∼20 μas does not provide enough detail to resolve important features such as radiative outbursts surrounding the accretion disk, nor to measure the shape and position of the photon ring at physically interesting levels. Here we simulate observations of general relativistic magnetohydrodynamic (GRMHD) models of the Kerr black hole M87 with the 2019 EHT configuration in conjunction with various satellite arrays to demonstrate how the extension of the EHT into space will benefit imaging. These satellite arrays are composed of two satellites just above Geosynchronous Earth Orbit (GEO) and yield an angular resolution of ∼3 μas, providing the ability to observe radiative outbursts as well as a highly resolved photon ring. These arrays provide sharper, more faithful images of M87 and demonstrate the ability to produce spatially resolved, time-resolved movies of the jet-launch region. We further examine the detectability of non-circularity in the shadow and the offset of its center due to frame dragging. Although these consequences of GR do not appear to be observable with the array configurations and calculations discussed, other array configurations may be suitable for directly detecting frame dragging around a black hole.

Software Support for GNSS Total Electron Content (TEC)
Brenna Royersmith, University of Colorado–Boulder (Presentation)
This project involves analyzing total electron content (TEC) data from the NSF CEDAR Madrigal database and creating maps that have a space weather parameter, the phase scintillation index, overlaid onto it. Scintillation parameters provide an estimate of how much disturbance a radio signal is likely to experience as it propagates through the ionosphere. Scintillation parameters representing both amplitude and phase scintillation are produced by specialized GNSS scintillation receivers. The amplitude scintillation index, S4, is defined as the ratio of the standard deviation of signal intensity and the average signal intensity. The phase scintillation index, sigma phi, is defined as the standard deviation of a detrended phase measurement. For high latitudes, the phase scintillation is more significant, so this is the parameter we analyzed. Both indices are defined over a specified period of time (typically 1- minute) and are available from specialized GNSS receivers. The NSF MRI Collaborative: Development of Monitors for Alaskan and Canadian Auroral Weather in Space (MACAWS), led by MIT Haystack Observatory, is in the process of deploying 35 new specialized GNSS receivers in Alaska and Canada. It was the scintillation data from this project, combined with scintillation data from the Canadian High Arctic Scintillation Network (CHAIN), that was used.

AERO
George Rubin, Swarthmore College  (Presentation)
The AERO and VISTA CubeSats will measure low-frequency, ionospheric radio emissions from Low-Earth orbit. The data volume generated from an orbit is on the order of one TB with the opportunity to downlink only about one GB per pass. Low-resolution summary data will be used to determine which high-resolution data to downlink. Data processing which includes integration in time, radio frequency interference excision, and plot formatting must be completed before the data can be viewed by the science team. A software package was developed in Python which successfully performs these functions.

Orbital Modeling for the AERO/VISTA CubeSat Mission
Kristen Ammons, Morehead State University (Presentation)
Auroral Emission Radio Observer (AERO) is a NASA H-TIDeS-funded mission with a goal of tracking the Earth’s radio aurora. AERO and its twin CubeSat— Vector Interferometry Space Technology using AERO (VISTA)— will reside in a polar orbit for the duration of its three-month mission. During this time, AERO/VISTA will measure direction of arrival, frequency spectra, and radio frequency emission occurrence rates. The mission has an additional technical objective of advancing the technology readiness level of its payload, the vector sensor.

Models of spacecrafts’ orbits are created using AGI’s Systems Tool Kit (STK), constrained to altitudes of 450 to 550 km and a noon/midnight polar orbit with a target local time of midnight. Having the nominal orbit allows for the determination of when a spacecraft will be passing through an auroral zone and if it will prove effective to take data during a given pass. Furthermore, one can determine when the spacecraft will be available for uplink and downlink over the Westford and Morehead ground stations. Finally, a decision can be made about the most effective time to perform critical housekeeping activities with as little infringement on data collection as possible. This includes determining when the two satellites can be in drag configuration to minimize the effects of drift due to differences caused by uncertainty in an along-track deployment. Further work with differential drag analysis has been done to determine differences in velocity that will ultimately result in loss of contact between the two satellites and at what point in time satellites will no longer be within the maximum allowable range in the event of loss of commanding capabilities.

Using Dark Clouds to Understand Distant Galaxies
Alexa Anderson, Yale University (Poster)
Gao & Solomon suggested that HCN could be used as a tracer of dense gas within molecular clouds. Star formation rates and dense gas mass had a clear relationship in galaxies analyzed by Gao & Solomon, according to their estimations. This relationship can be represented by αHCN, a ratio of dense gas (capable of star formation) mass to line emission luminosity. Here we test and improve αHCN to try to enable more accurate predictions of masses of molecular clouds in galaxies when masses are not easily inferred. We measured α_Q for many species Q within the cloud IC 5146. α_Q varied within different parts of the cloud and also between individual clouds. Additionally, αHCN calculated here was nearly an order of magnitude larger than that found in Gao & Solomon. Therefore, it is not straightforward to devise a universal α value that can be used to find dense gas mass in galaxies. Additionally, as we don’t know how HCN couples to dense gas, characterizations of star formation in galaxies is uncertain by an order of magnitude. Differing a values might result from the abundant diversity between molecular cloud properties, such as density and temperatures, which are also explored here.

Simulating Ground Plane Loss for EDGES-3
Ethan Bair, Cornell University (Presentation)
The Epoch of Reionization (EoR) is one of the major periods in the history of our universe, marking the formation of the first stars and the transition from neutral hydrogen to the mostly ionized hydrogen that exists today. The Experiment to Detect the Global EoR Signature (EDGES) looks at the 21 cm line of hydrogen in search of markers of this period in hopes of constraining the time period and learning more about the processes that dominated reionization. It is expected that photons from the very first stars redistributed the electrons in the 21 cm hyperfine states of the surrounding neutral hydro-gen. This would lead to a visible absorption feature in the spectrum for the 21 cm line. A profile like this was detected by EDGES-2 at 78 MHz, and EDGES-3 hopes to confirm this absorption feature. For EDGES-3, we simulated the ground plane loss to determine it’s behavior and eventually remove it from the signal when we start taking data. We modeled a 30 m by 16 m ground plane made from a meandering wire in the electromagnetic simulation software FEKO. The models were tested in free space, with a dielectric soil, and with a soil that was both dielectric and conductive. We found that for the free space and dielectric models, there was a lot of high resolution structure in the loss. However, the damping from the added soil conductivity is sufficient to erase that structure, and the remaining loss is much easier to fit. We also deployed the antenna in West Forks, Maine for a day to test the internal RFI. Internal noise leakage may be low enough, but unexpected external RFI means that additional tests may be necessary.

Enhanced Visualization of Geospace Data
Katherine Cariglia, Worcester Polytechnic Institute (Poster)
Data visualization is an important tool that can help to better understand observations of geospace made by various observational platforms around the world (i.e. the Millstone Hill radar). The Madrigal Database contains observations and summary figures from a large variety of instruments. The plots that are generated by the Madrigal Database currently use matplotlib and cannot be easily manipulated by the user. The goal of this project was to extend the functionality of data visualization techniques employed by the Madrigal Database using Glue. Glue is an open-source python library that is used to visualize and manipulate various types of data, with a specific focus on linking and overlaying visualizations of multiple different datasets. With the introduction of Glue, data can be imported into Glue’s GUI in a way that is comprehensible and highly customizable. Over the course of this project, Glue has been configured to import Madrigal data. The following data can now be imported: HDF5 files with Total Electron Content (TEC), scintillation data, data collected from incoherent scatter radar scans (specifically electron density), and data from the DMSP satellite. However, Glue is still a work in progress, and is suffering the growing pains of all new projects. The difficulty in customizing it to the geophysics community’s standard analysis methodologies may inhibit its adoption in the short term, but this tool has a lot of promise.

Analysis of High-Resolution Wind Fields of the Upper Atmosphere Observed with a Multistatic Meteor Radar Network
Samantha Carlson, Millersville University (Poster)
Observing the winds in the mesosphere and lower thermosphere (MLT) is crucial to understanding the energetics and coupling processes of the upper atmosphere, but they are difficult to measure with current techniques. The altitude range of interest limits in-situ measurements to rockets, which are infrequent and localized. Optical remote sensing instruments are sparsely-located, give only a local view, and are mostly limited to nighttime observations. Recent advances in meteor radars, which observe winds from about 80 to 100 km altitude through the Doppler shift of drifting meteor trails, hold the promise of temporally and spatially continuous coverage. New coded continuous wave (CW) meteor radars operating in a MIMO configuration with multiple inputs (transmitters) multiple outputs (receivers) collect enough statistics to estimate the complete MLT wind field over a wide area. A demonstration campaign with a prototype coded-CW specular meteor radar network called SIMONe was conducted in early November 2018 in northern Germany in a joint effort between the Leibniz Institute of Atmospheric Physics (IAP) and MIT Haystack Observatory. We analyzed 24 hours of data from this campaign to assess the wind observation capabilities of the system and test wind field estimation techniques. We computed altitude-resolved mean horizontal winds averaged over the radar field of view using the standard linear least squares method and observed effective resolutions of approximately 30 minutes and 1 km altitude. By applying a new Gaussian process regression technique, we estimated the complete MLT wind field and found it to be consistent with the mean winds. The wind field estimation technique was also tested with simulated data and shown to reliably reproduce mesoscale features. We conclude that coded-CW MIMO meteor radar networks, along with the new wind field estimation technique, show great promise for resolving outstanding questions about MLT dynamics.

Measuring the Spin of Sgr A* with the EHT
Michael Daniel, Whitman College (Poster)
General relativity predicts that the spacetime around a black hole is uniquely determined by its mass and spin. While black hole masses are often measured by observing the motions of orbiting stars or gas, spin measurements are much harder because they require observations of material very close to the black hole. The Event Horizon Telescope (EHT) provides the necessary angular resolution to see close enough to nearby black holes, including the galactic center’s black hole Sgr A*, to infer their spin. In this project, we examine whether EHT observations of gas falling into Sgr A* can be used to measure the spin of its black hole. We simulate EHT observations of infalling gas clouds embedded in a realistic accretion disk and then use shot analysis and the power spectrum density to investigate whether we can detect the orbital period of photons, which depends on the black hole spin. Both methods successfully obtain the expected orbital period of photons, and thus the spin of the black hole. Furthermore, the results from the shot analysis and power spectrum density method are consistent with each other. The ability for these processes to extract spacetime information shows promise for the EHT to be able to measure black hole spin.

Automated Data Analysis Software Package for The Antarctic Ice Penetrator Mission
Alvaro Guerra, Penn State University (Presentation)
The Automated Data Analysis (ADA) software package was developed for the 2019 summer MIT Haystack REU and this paper will go over its functionality and software validation. ADA was primarily developed as a data processing tool for MIT Haystack’s Antarctic Ice Penetrator mission. This mission will deploy two instruments on the Ross Ice Shelf (RIS) on the summer of 2020. Similar instruments have been deployed on the RIS in order to study various characteristics of the ice shelf. This mission aims to do real-time analysis of ocean forcing on the RIS in order to study the ice shelf’s response and further the understanding of Antarctica’s ice shelves. Each Ice Penetrator will contains a seismometer, and accelerometer, a GNSS antenna, and an iridium transmitter. With these scientific instruments we seek to study the ice shelf’s response to ocean forcing an the data collected will be transmitted to the iridium constellation and stored at the Incorporated Research Institutions for Seismology (IRIS) database. A computer at MIT Haystack will continuously run the ADA software package and autonomously retrieve data from IRIS and process it locally.

Expanding the Event Horizon Telescope into Space
Zoë Haggard, Pomona College (Poster)
With very-long-baseline interferometry (VLBI), the Event Horizon Telescope (EHT) is able to achieve resolution on scales of 20 µas, producing the first ever image of a black hole’s shadow. Nevertheless, the current array’s resolution is limited by the radius of the Earth, which provides baselines only long enough to resolve the shadow of two targets: our galaxy’s Sgr A* and the nearby M87*. Space-VLBI is one way to increase the EHT’s resolution. The addition of a constellation of telescopes at or above Geosynchronous Orbit (GEO) increases the longest baseline, opening up other black hole targets of varying angular sizes and flux densities. This project explores the systematic testing of the orbits required for a wide-reaching array of satellites, one able to image, with fidelity, targets at different locations and with structures down to 2 µas. We analyze the orbital-plane characteristics of such an array, looking at its Right Ascension node, inclination, and also height. Next, we test the performance by defining metrics, such as uv-filling and beam circularity. Then, we re-construct models from synthetic observations using the arrays that performed best under these metrics. In the end, we find that if a constellation of satellites is to be put above GEO, depending on the elements’ height, at least two satellites are needed to re-construct targets down to 3 µas. But, for array robustness and image quality, three to four are needed to resolve down to 2 µas across multiple targets. Many sources of interest fall within these scales and would be easily observed with such an array, enabling us to further understand the physical drivers behind AGN and black hole activity while also testing the predictions of general relativity in a variety of extreme environments.

FPGA Development for Real-Time Signal Processing
Huda Irshad, University of Massachusetts Boston (Poster)
The Auroral Emission Radio Observer (AERO) CubeSat will answer a number of open scientific questions associated with Earth’s Aurora and its electromagnetic emissions. AERO’s use of novel vector sensor technology will allow it to sense all the components of the electromagnetic field, opening up the possibility to direction of arrival estimation and polarimetry. The first step in realizing this is to create a real-time signal processing pipeline on a field programmable gate array (FPGA). A portion of this pipeline has been implemented to help understand the power consumption and the needed resources the FPGA design for the AERO mission. For this project Fast Fourier Transform (FFT), Finite Impulse Response (FIR) filter and digital down sampler were implemented within the FPGA of a PYNQ board. The PYNQ board can interface with Python on Jupyter Notebook, allowing for easy injection of test data from other software and rapid verification of hardware performance. Initial theoretical simulations of a digital down sampler with a low-pass filter, a FFT, and a digital down converter were done in MATLAB. The end result is individually functioning signal processing blocks that can be evaluated for their power consumption and FPGA resource usage. Additional work can be done to place the signal processing blocks into a single overlay that accounts for different latencies in blocks and information structure of data.

Auroral Radio Source Modeling for Vector Sensor Simulation
Abbey Marek, Clemson University (Presentation)
Auroral Emission Radio Observer (AERO) will be the first CubeSat to perform direction of arrival (DOA) calculations for sources of radio emissions in Earth’s aurora. DOA estimates are made possible with AERO’s unique vector sensor (VS), an orthogonal tri-loop and tri-dipole antenna which records all six components of a propagating electromagnetic wave. Ahead of AERO’s launch, the simulation of emissions from ground- and satellite-based measurements is used as a part of a larger effort to produce voltage level measurements from a VS simulator. A critical step in producing synthetic spectrograms of emissions seen by AERO is the production of an accurate model of the aurora which revolves in time. Data is taken from NOAA’s OVATION PRIME aurora power measurements. A planar fitting model is applied based on an auroral power restriction. This model provides an indication of the aurora’s footprint on Earth at any given date and time; it is also combined with AERO’s predicted orbit to generate auroral access reports, which can be used for data collection and system power requirement estimations. The aurora model is then used as a framework to generate radio source emissions with time accurate latitude and longitude restrictions. Modeling a wide variety of anticipated point sources allows for future matching of collected data with anticipated source modes. These modes include auroral kilometric radiation, auroral hiss, auroral roar, and medium frequency bursts. Each of the previous has unique occurrence rates, durations, altitude ranges, frequency ranges, frequency centers, and intensities. Additional radio wave characteristics such as polarization angles and phase are also considered. A frequency, time, and spectral intensity plot is produced which combines the source times series data with the orbital model. Future work will include much greater accuracy of plasma effects on wave propagation and generation.

Imaging of Relativistic Jets from Super-Massive Black Holes
Cecilia Siqueiros, MIT (Poster)
In recent years new imaging algorithms have been developed for the purpose of creating the first image of a black hole. Though these new algorithms have shown improved performance and provided added flexibility in imaging, they have not yet been applied to other very long baseline interferometry (VLBI) observations of faint sources, such as high redshift active galactic nuclei (AGN). An AGN is the region at the extremely luminous center of a massive galaxy where a supermassive black hole emits powerful jets of magnetized plasma caused by the dissipation of gravitational potential energy by friction within the encompassing accretion disk. We used the Sparse Modeling Imaging Library for Interferometry (SMILI) to image nineteen AGN theorized to be young. Our motivation was to explore the capabilities of SMILI imaging on faint sources as well as to analyze the observed structures produced by powerful young AGN jets interacting with nearby dense and clumpy interstellar medium (ISM). The data, of frequencies 1.4 GHz and 5 GHz, was obtained collectively by the enhanced Multi Element Remotely Linked Interferometer Network (e-MERLIN) and the Very Long Baseline Array (VLBA). We compared our results with separately produced CLEAN algorithm images of some sources. These CLEAN comparisons as well as the consistencies of SMILI imaging across multiple frequencies (1.4 GHz and 5 GHz) validated our image results. Our images confirmed the presence of compact structure for most of the AGN, consistent with the expected structure size of a young AGN.

A New Empirical Model for Ionospheric Total Electron Content
Cole Tamburri, Boston College (Presentation)
In recent years new imaging algorithms have been developed for the purpose of creating the first image of a black hole. Though these new algorithms have shown improved performance and provided added flexibility in imaging, they have not yet been applied to other very long baseline interferometry (VLBI) observations of faint sources, such as high redshift active galactic nuclei (AGN). An AGN is the region at the extremely luminous center of a massive galaxy where a supermassive black hole emits powerful jets of magnetized plasma caused by the dissipation of gravitational potential energy by friction within the encompassing accretion disk. We used the Sparse Modeling Imaging Library for Interferometry (SMILI) to image nineteen AGN theorized to be young. Our motivation was to explore the capabilities of SMILI imaging on faint sources as well as to analyze the observed structures produced by powerful young AGN jets interacting with nearby dense and clumpy interstellar medium (ISM). The data, of frequencies 1.4 GHz and 5 GHz, was obtained collectively by the enhanced Multi Element Remotely Linked Interferometer Network (e-MERLIN) and the Very Long Baseline Array (VLBA). We compared our results with separately produced CLEAN algorithm images of some sources. These CLEAN comparisons as well as the consistencies of SMILI imaging across multiple frequencies (1.4 GHz and 5 GHz) validated our image results. Our images confirmed the presence of compact structure for most of the AGN, consistent with the expected structure size of a young AGN.

Open Source Drone Platform for Radio Science using Software-Defined Radios
Devon Alcorn, University of Oklahoma (Presentation)
Software-defined radios (SDRs) find their strength in their ability to rapidly adapt for different radio applications while maintaining a relatively small form factor. Inexpensive options of these devices have also become available on the market in recent years and have been heavily adopted by the radio science community. In another vein of adaptability, the past few years have brought the popularity of small unmanned aerial systems (UASs), specifically quadcopter-style drones, for various uses that often involve carrying small payloads. As these UASs have popularized, technology allowing for automated flights and accurate positioning of the aerial systems have also become common and readily available. As a result, the possibility of combining software-defined radios and UASs to create a general platform that can be used for a wide variety of radio science applications has become viable. Within this project, we develop an open- source drone design that can be adapted to a multitude of uses. The design features a UAS controlled by a Pixhawk, an open source flight controller unit (FCU); the drone carries a small software-defined radio device as well as a companion computer. Through the companion computer the user can interact with the FCU to both record flight data and execute flight commands, as well as control the software-defined radio to record RF data using the Haystack developed open source software package Digital RF. This platform has gone through numerous flight tests to ensure it can operate safely with the companion computer and SDR. As an example application of this platform, we fly above an emitting antenna and use the software- defined radio to collect time and position tagged RF data that could be used to map the antenna pattern. This first test will use an antenna with a known pattern to verify this technique for future uses.

Radio Location Finding Using Software Radio for Conservation Ecology
Sean Beverly, Fitchburg State College (Presentation)
This project works to apply radio direction finding techniques to radio tags used by biologists in the field for animal tracking and conservation. This development is motivated by a need for a far quicker and easier way to locate animals that have been radio tagged. This will enable long term monitoring of endangered species populations by cutting down on person-hours required in the field. We show that low-cost software defined radios have the potential to be used for radio direction finding as part of a multi-element array or as receivers for an electromagnetic vector sensor. We will discuss an initial prototype design utilizing a small computer, software defined radios, a GPS receiver, an inertial measurement unit, and power supply which can be used in either a portable or stationary capacity. Initial results indicate that field detection of turtles tagged with VHF radio transmitters is possible along with estimate of phase information needed for angle of arrival determination. We will discuss practical issues related to field use of the instrumentation based on field experiments. Our design could be improved using a more robust code to detect radio tag pulses and filter interference. Field calibration of the system will also be a challenge. In practice it was also noted that self interference was produced by several components of the design, requiring use of attenuation materials that added to the weight of the unit. Goals for future evolution of the system include development of more compact hardware, improved user interface, detection and display of multiple tags simultaneously, and location estimation from multiple measurements.

Spectrometers for the Ground Observation of Mesospheric Water and Ozone
Rachel Boedicker, Case Western Reserve University (Presentation)
In order to track the concentrations of molecules such as ozone and water in the atmosphere, spectrometers are used to measure the emission frequencies dictated by the molecules’ quantum structure. Observations are often made from above the mesosphere using infrared frequencies. However, ground based measurements can be made less expensively using lower line frequencies, granted the data can be reliably acquired through the atmosphere. The original intent of this project was the observation of the 13 GHz hydroxyl line using a ground-based microwave spectrometer. However, due to lack of significant signal strength in initial observations, the project shifted focus to the 22 GHz water vapor line. Additionally, a previous system for ozone was updated to work with 8 collecting channels.

Analysis and Improvements upon Covariance Estimation Algorithms for Direction of Arrival Estimation
Daniel Dopp, University of Kentucky (Presentation)
Electromagnetic vector sensors are an emerging antenna technology which open the door for improvements upon current electromagnetic sensor capabilities. Vector sensors provide a full description of the state of the electromagnetic field at a single point in space, meaning they are sensitive to incoming signals from all directions and with any polarization. This complete electromagnetic wave information enables direction of arrival estimation without a traditional array of elements or the accompanying deployment effort. In situations where the use of additional elements comes at a premium, such as portable direction-finding or satellite sensors, vector sensors have the advantage of simpler logistics and reduced cost. In this talk I discuss the capabilities of covariance estimation algorithms for point source direction of arrival estimation using simulated vector sensor measurements. Results show that these algorithms maintain accuracy in resolving point sources even when subjected to increasingly fine angular resolution constraints and are highly effective at resolving directions of arrival for a limited number of sources. Current limitations of these algorithms center around a slowdown in convergence time and corresponding decrease in accuracy when a large number of signal sources are introduced. Secondary issues arise in the form of computation time, in which high resolution source finding becomes computationally expensive. In addition to our analysis of current algorithms, we also propose potential improvements using regularization techniques and machine learning based augmentations to the source finding process. Initial results of these improvements and potential further avenues of exploration are discussed.

Comparison of Millstone Hill Plasma Line and Lowell Digisonde Plasma Frequencies: A Statistical Study
L. Claire Gasque, Dartmouth College (Poster)
Millstone Hill’s Incoherent Scatter Radar (ISR) began continuous plasma-line (PL) monitoring in 2015. The ISR PL technique allows highly accurate measurements of Langmuir mode wave resonance frequencies from the ionospheric plasma. At Millstone Hill, PL monitoring was initially intended to supply electron density measurements to the ISR’s ion line data for calibration purposes. Prior to this project, electron densities were calculated using the cold-plasma approximation that the Langmuir mode wave frequency, as measured by the PL, is equal to the plasma frequency. This project analyzes the accuracy of this approximation by comparing two years of Langmuir mode frequency measurements from Millstone’s PL monitoring with direct plasma frequency measurements from the nearby Lowell digisonde. The results indicate that there is a statistical offset between the two frequencies, with the Langmuir mode frequency 1.24% higher than the plasma frequency, on average. Applying a temperature correction to the Langmuir mode frequencies tends to resolve the discrepancy for lower frequency cases, but overcorrects higher frequencies. Future work is necessary to determine the technical or physical explanations for the different responses in these populations.

Millstone Hill Plasma Line Full Profile Project
L. Claire Gasque, Dartmouth College (Presentation)
Incoherent scatter radar (ISR) plasma-line (PL) techniques allow highly accurate measurements of Langmuir mode wave resonance frequencies from the ionospheric plasma. These measurements are well- suited to detecting and characterizing small fluctuations in the ionosphere, such as those produced by traveling ionospheric disturbances (TIDs). In 2015, increased radar bandwidth, additional processing power, and improved data reduction techniques allowed the Millstone Hill ISR to begin continuous PL monitoring. This monitoring was initially intended for calibration use, and processing constraints limited it to run at low range resolution. However, promising early results led to the desire to develop this technique further for scientific applications. For this project, I worked to improve the PL range resolution by modifying the PL production code and processor allocation. Ultimately, we increased the resolution from 60km to 7.5km, an 8-fold improvement. As of August 2, 2018, the new code is officially in production and will be used to gather data in all future PL experiments.

Dynamical Reconstruction of Blazar Source 3C 273 at 43 GHz and 15 GHz
John Hunter, Boston University (Presentation)
The Event Horizon Telescope (EHT) uses very long baseline interferometry to image supermassive black holes in the centers of galaxies. Currently, this array is able to handle nearby sources, such as SgrA* and M87, due to their large angular size and limited variability. However, we hope that the EHT will be able to handle a larger number of differing sources as more telescopes are added. New imaging techniques are being developed to exploit the full potential of the EHT’s high angular resolution and also offer the promise of improving the image quality of lower-frequency VLBI data. In order to accomplish this, we develop a pipeline in the sparse modeling imaging library (smili) that takes real VLBA data of the blazar source 3C 273 at both 43 GHz and 15 GHz and dynamically reconstructs the evolution of its jet over 10 and 22 years, respectively. We then conduct a wavelet-based decomposition and analysis of significant structural patterns in the jet by implementing a newly developed wavelet-based image structure evaluation (WISE) algorithm into smili. We find that our new pipeline is able to handle the shifting cores typical of blazar sources with surprising accuracy and smoothness. We also report a number of interesting discoveries in the behavior of knot-generation per epoch cycle, velocity and acceleration profiles of the jet, and lifetimes of these knots.

Development of an Avionics System for Autonomous Antarctic Ice Penetrator Power Budget Iridium Power Measurement
Samuel Mekonnen, University of Massachusetts (Poster)
The stability of the massive Antarctic ice sheet, hence sea-level change, depends critically on the stability of the floating ice shelves that rim the continent and buttress the flow of glaciers, ice streams, and continental ice towards the ocean. Because ice shelves lie at the ocean-ice-atmosphere interface, they respond to ocean and atmospheric forcings. It has recently been suggested that long-period infragravity ocean waves may be a mechanism that triggers the collapse of a thinning ice shelf under changing climate conditions. MIT Haystack Observatory is developing a seismo-geodetic ice penetrator instrument to study the response of Antarctic ice shelves to infragravity waves. This REU project builds on a prototype system developed by the students of the 16.83 Space System Engineering capstone course at the MIT Aero&Astro Department. The scientific sensors include a broadband seismometer and a geodetic-quality GPS receiving system. The instrument is designed to operate autonomously and continuously for a year during which it will transmit science and engineering data from the field to a server on the Internet via the Iridium satellite system. We describe the Iridium power model, which includes a 9523 Iridium transceiver packaged in a A3LA-R modem. The system runs on primary batteries, hence power budget has a significant impact on mass budget and, because the system is air-dropped, also on aerodynamic performance, and ice impact and penetration.

Black Hole Imaging with Space-Based Telescopes in Extended Orbits
Maura Shea, Wellesley College (Poster)
The Event Horizon Telescope (EHT) currently has sites around the globe, effectively forming a telescope with a diameter of the Earth through the use of Very Long Baseline Interferometry (VLBI). The EHT currently images the supermassive black holes at the center of M87 and Sagittarius A*, as they have the largest apparent black hole shadow diameters. The addition of space-based telescopes would expand the diameter of the EHT, potentially allowing for higher fidelity imaging of current sources as well as sources with smaller shadows. This paper explores the potential benefits of adding telescopes in extended orbits to the EHT. To test the effectiveness of orbital patterns, we first generate models of shadow sources with various black hole shadow sizes, then create model telescope arrays that include telescopes in different orbits. With these arrays, we create image reconstructions of the models using closure phases and visibility amplitudes. We determine that by including a Geostationary Earth Orbit satellite and an eccentrically orbiting satellite, we can successfully reconstruct high-fidelity images of the next tier of shadow sources, from the Sombrero Galaxy (6.6 microarcseconds) down to a shadow diameter of 3 microarcseconds. We find that extending the Event Horizon Telescope to include satellites with extended orbits both significantly improves the reconstructed images of its primary targets and allows for the imaging of sources more than an order of magnitude smaller than Sagittarius A*.

Autonomous Spacecraft Navigation using Millisecond Pulsars
Vincent Trung, San Jose State University (Presentation)
Spacecraft navigation has been and always will be a necessity to probe the universe more deeply. Although the current spacecraft navigation system is effective through the use of Doppler radars and miniature satellites, it is expensive as it depends on the Deep Space Network (DSN), a limited resource that will come under increasing strain with the increasing number of satellites that require navigation support. Theoretically, spacecraft may navigate autonomously by depending on data already in the sky. Such data may come from the exquisitely regular and predictable emission from pulsars, thus allowing for spacecraft to detect their own position independent of ground-based control. By using and modifying the current Small Radio Telescope (SRT) at Haystack, we will explore the spacecraft navigation potential of pulsars from L-band data and characterize terrestrial radio-frequency interference.

Superresolving Black Hole Images with Full-Closure Sparse Modeling
Chelsea Crowley, Cape Cod Community College (Poster)
It is believed that almost all galaxies have black holes at their centers. Imaging a black hole is a primary objective to answer scientific questions relating to relativistic accretion and jet formation. The Event Horizon Telescope (EHT) is set to capture an image of two nearby black holes, one at the center of the Milky Way (Sagittarius A*) and the other in Virgo A (M87). Sparse imaging techniques have shown great promise for reconstructing high-fidelity super-resolved images of black holes from simulated data. Previous work has included the effects of atmospheric phase errors and thermal noise, but not systematic amplitude errors that arise due to miscalibration. We explore a full-closure imaging technique with sparse modeling that uses closure amplitudes and closure phases to improve the imaging process.

This new technique can successfully handle data with systematic amplitude errors. Applying our technique to synthetic EHT data of M87, we find that full-closure sparse modeling can reconstruct images better than traditional methods and recover key structural information on the source, such as the shape and size of the predicted photon ring. These results suggest that our new approach will provide superior imaging performance for data from the EHT and other interferometric arrays.

Calculating Total Electron Content with Glonass
Caileigh Fitzgerald, Bunker Hill Community College (Presentation)
Total Electron Content (TEC) is a measure of electron density along a line of sight from a ground-based receiver to a GNSS satellite for a given point in time and space. The Madrigal database incorporates global maps of TEC collected from approximately 6000 receivers. The current software used to populate the Madrigal database calculates TEC from an array of data collected from each GNSS receiver using only the GPS constellation. With multiple countries developing their own Global Navigation Systems, there is a need to update the existing software used by Madrigal to process data from these additional constellations. This project involved the incorporation of the Globalnaya Navigazionnaya Sputnikovaya (GLONASS) data. Unlike GPS, GLONASS, uses an FDMA, (Frequency Division Multiple Access) code using two unique frequencies per satellite. The particular FDMA code used depends on the satellite transmitting. GLONASS also has a separate navigation file with different types of data stored for the ephemeris calculation, forcing an additional step of calculating the sidereal time to get an accurate ephemeris. This talk with outline the work that has now allowed the software to process GLONASS and GPS data. With the data from the GPS’s 32 satellites and GLONASS’s 24 satellites, TEC will be calculated with higher density and fewer data gaps over the globe.

Optimizing the Sidelobe Properties of Radar Waveforms
Kavish Gandhi, MIT (Poster)
One of the fundamental problems in radar signal processing is removing or minimizing unwanted sidelobes that remain after the application of a matched filter. In the past, most work has focused on tackling this problem for binary codes in the zero-frequency domain, and minimal codes have been found successfully through both exhaustive means and the use of optimization algorithms. This project develops a number of optimization algorithms to solve this problem, including simulated annealing, genetic, evolutionary, and particle swarm approaches. We also design these algorithms to solve the more general problem of minimizing sidelobes in range-doppler space for binary codes, polyphase codes with a fixed generator, and arbitrary polyphase codes. We show that we can generate optimal binary and polyphase codes comparable to those in the literature, compare and analyze the relative success of the various optimization algorithms, and present a number of novel codes with optimal peak sidelobe values in range-doppler space. We also extend these algorithms to the generation of alternating binary and near-alternating polyphase codes with lengths 8-20, showing marked sidelobe improvement over single codes of the same cumulative length. Finally, we reimplement these algorithms to generate near-perfect codes of lengths of at least 1000, waveforms that will be useful for imaging farther objects such as the moon.

Extraction of Black Hole Shadows Using Ridge Filtering and the Circular Hough Transform
Ryan Hennessey, Saint Anselm College (Poster)
Supermassive black holes are widely considered to reside at the center of most large galaxies. One of the foremost tasks in modern astronomy is to image the centers of local galaxies, such as that of Messier 87 (M87) and Sagittarius A* at the center of our own Milky Way, to gain the first glimpses of black holes and their surrounding structures. Using data obtained from the Event Horizon Telescope (EHT), a global collection of millimeter-wavelength telescopes designed to perform very long baseline interferometry, new imaging techniques will likely be able to yield images of these structures at fine enough resolution to compare with the predictions of general relativity and give us more insight into the formation of black holes, their surrounding jets and accretion disks, and galaxies themselves. Techniques to extract features from these images are already being developed. In this work we present a new method for measuring the size of the black hole shadow, a feature that encodes information about the black hole mass and spin, using ridge filtering and the circular Hough transform. Previous methods have succeeded in extracting the black hole shadow with an accuracy of about 10- 20%, but using this new technique we are able to measure the shadow size with even finer accuracy. Our work indicates that the EHT will be able to significantly reduce the uncertainty in the estimate of the mass of the supermassive black hole in M87.

Model-Based Light Curve Analysis
Bethlee Lindor, Princeton University (Presentation)
Light curves show the brightness of stellar objects over a period of time. Variations in these time series can occur due to changes in stellar characteristics, planet and moon transits, atmospheres, debris, comets, other phenomena, or noise. The Kepler mission, for example, has confirmed most of the 3,500 extra-solar planets to date by analyzing more than 150,000 stars with the transit method. A current challenge in light curve analysis, however, is the inference of a planetary system given a particular light curve.
To assist scientists in this challenge, this project conducts case study simulations in the Blender Raytracer. The goal is to simulate a variety of alternative scenarios and reveal rivaling explanations for complex stellar systems which would normally be difficult to derive analytically. The presentation will also illustrate how this technique could improve our understanding of Tabby’s star (KIC 8462852) which the media has sensationally claimed to be surrounded by alien megastructures. If such megastructures existed, what would their light curves look like?

Data Tools and Processing Pipeline for the Mars Oxygen ISRU Experiment (MOXIE)
William Maynard, University of Massachusetts Amherst (Poster)
In recent years, there has been a resurgence in interest in the field of manned space exploration, in particular, a manned mission to mars. Such a mission requires years of planning and experimentation beforehand in order to prepare. One such experiment is the Mars Oxygen ISRU Experiment (MOXIE), which will be part of the Mars 2020 rover mission. ISRU stands for In-Situ Resource Utilization, which means taking advantage of the resources at the mission location to support the functions of the mission itself or “living off the land”. ISRU makes longer range missions such as a manned mission to Mars much more feasible by reducing the mass needed to be launched from earth, therefore saving launch expenses. MOXIE is an experiment to determine the viability of creating oxygen from the carbon dioxide that makes up 96% of the Martian atmosphere. MOXIE consists of ten solid oxide electrolysis (SOXE) cells arranged in two five cell stacks. The cells produce oxygen by using electrolysis to break down CO2 into carbon monoxide and oxygen. MOXIE is a test case for technology that could hopefully be expanded to a much larger scale in order to create propellant for a Mars Ascent Vehicle for the return trip of a manned mission in the 2030’s. As would be the case in any experiment, a large amount of data will be collected from MOXIE and once that data is compiled it needs to be processed and refined. A data pipeline has been created to detail the steps the data takes from the raw MOXIE data sent from the rover to the fully refined data. A suite of MATLAB tools and functions have been created to read, derive, and plot the data at the different steps of the data pipeline.

Development of an Avionics System for Autonomous Monitoring Applications
Zain Merchant, The University of Texas at Dallas (Poster)
MIT Haystack Observatory is interested in studying the current state of the cryosphere through the response of the Antarctic ice-shelf to ocean and infragravity waves. Due to the dangers of conducting manned research in such an environment, a proposal has been made to engineer an air-dropped data collection system to autonomously record and transmit geodetic / seismic data measurements. A subsection of this project entails the development of an avionics system to collect, process, record, and transmit data, while maximizing efficiency (most notably, in power). In this paper, we describe our comparison of two different avionics system models and the work we have made towards a prototype system to be used for such an application.

Studies in Autonomous Navigation with Pulsars and Astronomical Masers
Sarah Norris, Morehead State University (Presentation)
The development of an autonomous navigation system for spacecraft is an important step towards expanding our interplanetary exploration capabilities and, consequentially, our understanding of the universe we live in. This project explores the possibility of reducing, and potentially eliminating, the need for ground-base control for CubeSats and SmallSats by enabling spacecraft to observe astronomical sources and determine their own instantaneous velocity and position for navigation. An extension of current reference frames to include sub-catalogs of stable pulsar and astronomical maser sources, as well as the development of computational capabilities and antennas capable of utilizing both sub-catalogs, will allow positions and velocities of spacecraft to be determined autonomously relative to the reference frames of Earth and other planets within our Solar System. The focus of this particular study involved multiple ground observations of 6.7 GHz Methanol maser lines made with the Westford 18.3m radio telescope. Four sources were observed and their spectra analyzed: Cep A, NGC 7538, W3(OH), and S 252. Correlations between relative velocities from multiple observations of these sources show that Doppler shifts in the spectra of these maser lines may be used to resolve the rotational velocity of the Earth in ms-1, relative to the times and locations of the observations. This concept can be applied to determining velocities of spacecraft using delays in future observations.

Time Series Feature Detection
Evan Wojciechowski, University of Illinois at Urbana-Champaign (Presentation)
This project explores data mining and visualization techniques to fa- cilitate the discovery of features in time series data with the goal of char- acterizing various geophysical and astrophysical phenomena. The tool- box implements a set of Python functions for Fourier analysis, Wavelet analysis, and empirical mode decomposition. In addition, the toolbox offers visualizations for these transforms as well as spiral plots for the visual detection of periodicity in data. The implementation will be avail- able through the scikit-discovery open source package published by MIT Haystack on Github.

Evolution of Star Formation of Dwarf Galaxies within Extragalactic Cluster Substructures
Haylee Archer, University of North Dakota (Presentation)
Galaxy clusters form the largest structures in the universe and provide an environment to study galaxy evolution. In particular, dwarf galaxies with low mass are highly susceptible to external influences. Therefore, to understand the star formation history of dwarf galaxies, effects from the environment need to be identified and separated. To address this problem, we examine a sample of galaxies from the Sloan Digital Sky Survey (SDSS). A key part is the characterization of galaxy clusters and cluster substructures, which we address using VariantDBSCAN, an algorithmic technique extending the well-known Density-Based Spatial Clustering of Applications with Noise (DBSCAN). Our approach can vary clustering parameters that each lead to alternative clustering models of galaxy clusters with potentially different shapes and densities. Scientists can thus generate and explore potential evolutionary histories in a semi-automated way.

PyCloudPath: A Cloud-Scalable Pipeline Framwork for Data Processing
Cory Cotter, University of Wisconsin (Presentation)
Radio science systems using software radio receivers are now capable of collecting data at astonishing rates. Processing these data in a timely and useful manner can require the use of multiple computer systems each of which may have many cores that operate in parallel. PyCloudPath is a Python framework and module that allows for simplified creation of multiprocess, multi-machine programs in the form of pipelines. In its basic form, users only need to create an initialization file with the pipeline information, implement one method per stage, and implement a head to handle pipeline input. PyCloudPath can operate in a cloud environment and dynamically allocate processing power on demand. The pipelines created can use multiple virtual machines and the framework enables the user to scale a pipeline to increase the computation available to a given processing task. Several scaling methods have been implemented including forking pipelines at a given stage, increasing the number of processes per stage, extending pipelines across multiple machines, and replicating pipelines. The user can interact with PyCloudPath pipelines in real-time by sending commands to each individual stage and see the immediate results by viewing live output and logging information about the program state. Initial tests of PyCloudPath have focused on radio science signal processing and include a spectrogram and passive radar demonstration. We have demonstrated the scaling of the processing for these applications using the Geospace cloud computing system and data inputs from RAPID prototype software radio hardware.

Low Frequency Solar Imaging Using the Murchison Widefield Array and CASA
Meagan Crowley, University of Massachusetts Boston (Presentation)
Radio images of the Sun from an event of high solar activity on November 4, 2015, are presented using interferometric data from the Murchison Widefield Array (MWA). The MWA is a low frequency, high resolution radio telescope spanning 3 km in the radio quiet Australian Golden Outback, making it particularly suitable for radio imaging of the Sun. Low frequency, high resolution solar observations provide key insights about the structure and spectra of solar emissions and allow for superior modeling and prediction of solar activity. Methods of producing solar images using the imaging program CASA, developed by the National Radio Astronomy Observatory (NRAO) are discussed, as well as the success of the results and their interpretations. The advancement of solar radio imaging with the aid of the pioneering technology of the MWA has opened the door to enhanced solar activity predictions and modeling and has broadened the capabilities of low frequency interferometry. The images shown will provide a case for the continuing advancement of low frequency solar imaging.

What Happens in the Thermosphere if the Stratosphere is Strongly Disturbed?
Jolene Fong, Wellesley College (Presentation)
We investigate the possible stratosphere-thermosphere coupling at high latitudes, where the cusp of the Earth’s magnetic fields lie, using Sondrestrom Winter Ionosphere Model (SWIM) and Sondrestrom ISR data from the last 15 winters (2001-2016). This position is of particular interest because of the ionosphere’s strong dependency on solar and geomagnetic activity, as well as its proximity to the stratospheric polar vortex. After using the model to remove daily variations, seasonal variations, and variations due to solar flux and geomagnetic activity, anomalies in the data were compared to anomalies in stratospheric winds and temperatures. Our results so far show a possible dependency between ion temperature and stratospheric winds, with higher correlations found every six hours. This dependency is intensified during years of Sudden Stratospheric Warnings (SSWs), where sudden changes in the winter hemisphere westerly winds can result in an increase in stratospheric temperatures and sometimes even reversal of the polar vortex. Studying the connection between these anomalies can help us link stratospheric events to ionospheric disturbances, and therefore help us predict the state of the ionosphere using meteorological events, which we currently know up to several days in advance.

Dust is Everwhere: Opportunistic High Power UHF Radar Measurements of Meteoroid Properties
Christina Migliore, Northeastern University (Presentation)
Meteoroids entering the atmosphere help to provide insight into the behavior of the ionosphere. The radar scattering from a dense ball of plasma around an ablating meteor, known as meteor head echo, is key to the study of meteoroid properties. Ultra high frequency (UHF) radar measurements of meteor head echoes and their properties are frequently only collected as a dedicated meteor experiment, but detection is possible in the majority of radar experiments if the right processing is applied. A meteor data pipeline was created in order to detect and processes meteors on all data collected by the radar. In order to provide a higher SNR and reduced range ambiguity, this pipeline correlates the received signal to the transmitted signal by using a matched filter. To account for the velocities of the meteoroids the data is Doppler corrected by Discrete Fourier Transform (DFT). Meteor head echoes are identified and clustered into individual events based on signal-to-noise ratio (SNR), time, range, and velocity which are then saved for statistical analysis. This pipeline additionally plots histograms of range, range rate, duration, and SNR. An experiment on July 26, 2016 using the UHF Millstone Hill radar in Westford, Massachusetts found 272 meteors between 7 am to 11 am roughly at a rate of 96 meteors per hour with the peak at 7 am. Comparing these results to other past meteor experiments found that the meteor trends agree. This data pipeline will help to create an abundance of statistics on meteors in order to provide a better platform for meteor science.

Investigating Dual Frequency Software GPS Signal Processing for Geodetic-Quality Positioning
Manuel Paul, California State University (Presentation)
Generally used for basic civilian positioning, the Global Positioning System (GPS) has been pushed beyond its original design and has become a powerful tool for high-precision geodetic applications in geosciences, and beyond. Current dual frequency GPS hardware receivers can provide sub-millimeter level precision, but their closed designs, limited interfaces, and high prices can become a limitation to their applicability. Software receivers are an alternative, but, to the best of our knowledge, available implementations are limited to single frequency receiving systems. We will present our first steps on digital signal processing techniques and algorithms towards converting GPS software receivers from single to dual frequency systems.

A Fully Automated Scanning RFI Monitoring System for VGOS Site Surveys
Cadence Payne, Morehead State University (Presentation)
MIT Haystack Observatory has established itself as a renowned leader in the field of Very Long Baseline Interferometry, VLBI. Haystack is leading the development of a wideband signal chain for the VLBI Global Observing System (VGOS) component of NASA’s Space Geodesy Project. With the deployment of these new wideband VGOS stations there exists the threat of radio frequency interference. This interference, both naturally formulated and manmade, poses degradation to the sensitivity of the station’s instrumentation and can result in the disruption of a station’s ability to conduct successful VGOS observations. This threat motivated engineers to design a fully automated scanning RFI monitoring system to observe and characterize these unwanted signals at prospective sites prior to the construction of these VGOS stations. The current project’s responsibility involves improving the current design of said system. Before beginning the designing process, the previously developed system underwent testing and analysis to provide a better understanding of its functionality and of the general realm of radio frequency interference. With the help of Haystack engineers and technical staff, a refined design for the previously composed scanning system is underway. The design works to incorporate a smarter motor for simpler maneuvering, utilize software development for instrument control, and integrate a more portable and powerful spectrum analyzer capable of capturing observed spectra in real time. Other improvements to system simplicity and functionality are under consideration.

The Resurrection and Reporposing of the VLG-10 (P2) Maser
Cadence Payne, Morehead State University (Poster)
As a secondary project, we conquered the task of resurrecting MIT Haystack’s VLG-10 (P2) Hydrogen MASER. The MASER, previously housed at the SMA observatory in Mauna Kea, sat stagnant at MIT Haystack. The MASER successfully powered back on and currently sits, happily stabilized, in house at the observatory. It will relocate to Morehead State University in Kentucky with its primary purpose being the time standard for the university’s 21m dish as it undergoes integration into NASA’s DSN. P2 underwent Allan Deviation testing in comparison with the NR7 MASER that also resides at MIT Haystack, and has proven itself capable of meeting the frequency stability specifications required for the DSN. The P2’s Hydrogen bottle sits at a significantly low PSI, resulting in the design of a new configuration for the bottle replacement prior to it being delivered to Morehead State.

Studying Earth Surface Deformations with InSAR and GPS
Juliet Pilewskie, University of Colorado (Presentation)
Remote sensing techniques, such as Global Positioning System (GPS) and Interferometric Synthetic Aperture Radar (InSAR), are important for measuring and modeling the deformation of the Earth’s surface. GPS gathers precise, real-time measurements with high temporal resolution, while InSAR provides accurate measurements over large spatial regions. Ongoing work continues to face difficulties in combining the two techniques in order to utilize the superior time resolution from GPS and the higher spatial resolution of InSAR. In this project, we explore potential methods to fuse the two data sets using InSAR data from two different sources, Uninhabited Aerial Vehicle SAR (UAVSAR) and ASAR-ENVISAT. We generate interferograms from Single Look Complex (SLC) stacks provided by UAVSAR to study surface deformations due to groundwater changes in California, and examine InSAR images from ASAR-ENVISAT to explore volcanic activity in the region surrounding the Kilauea volcano in Hawaii. Building on the ASAR-ENVISAT data, we focus on Kilauea and incorporate simultaneously recorded GPS data. These two data sets can be incorporated into a data processing pipeline that allows for efficient exploration of many-dimensional parameter space with the hopes of increasing the level of precision and reliability of both surface deformation patterns and volcanic expansion centers.

Super-resolution Polarimetric Imaging of Black Holes using the Event Horizon Telescope
Mollie Pleau, Smith College (Poster) (Presentation)
Black holes are thought to reside in the centers of many galaxies; however, due to their diminutive size, we have yet to directly detect and image a black hole. The Event Horizon Telescope (EHT), a global array for 1.3mm very long baseline interferometry (VLBI), has been designed to observe and image the supermassive black hole in the center of the Milky Way (Sagittarius A*), as well as the one in the center of the nearby giant elliptical galaxy M87. The nominal resolution of the EHT is around 30 μas, comparable to the size of the black hole’s event horizon. For this reason, we require super-resolution to accurately reconstruct images in total intensity and linear polarization. High fidelity polarimetric imaging can be used to test general relativity and to characterize the magnetic field structure surrounding black holes, which is important for understanding its role in mediating the innermost accretion and outflow region. We employ new sparse imaging techniques based on compressed sensing for linear polarimetry. Using synthetic data of M87 observations with the EHT, we find that our new techniques improve upon the standard CLEAN by a factor of ten regardless of resolution, as measured by the differences in mean squared error (MSE). We conclude that compressed sensing proves to be an effective method for linear polarimetric imaging.

Towards Understanding the Data from the Next-Generation VLBI Geodetic Systems
Shelby Price, Morehead State University (Presentation)
Very Long Baseline Interferometry (VLBI) is a fundamental technique used to determine important geodetic parameters. VLBI can provide estimates of Earth Orientation Parameters (EOP) such as UT1 and UT1-UTC, as well as the celestial pole offsets, and contributes to the determination of the International Celestial Reference Frame (ICRF) and the International Terrestrial Reference Frame (ITRF). Because VLBI is such a useful and necessary tool, improvements to the VLBI technique are essential to the advancement of geodesy. As such, the VLBI Global Observing System (VGOS) has been planned as a way to improve upon the legacy geodetic VLBI system. The VGOS system will use smaller radio antennas with shorter slewing times, coupled with broadband feeds to achieve accuracies greater than 1 millimeter in baseline length estimates, or about 3 picoseconds in time delay measurements, between stations. The broadband hardware for this new system has already been designed and recently implemented at the Kokee Park Geophysical Observatory (KPGO) as well as a few other stations to serve as a proof of concept test. The goal of this project is to analyze data obtained with this new hardware in order to compare the VGOS system with the legacy system in terms of performance and results. Current progress will be presented.

Algorithmic VLBI Baseline Selection in Radio Astronomy Applications
Aleksandra Safonova, University of Arizona (Presentation)
This project develops an algorithmic method for incrementally selecting VLBI baselines under constraints such as reducing the number of required correlations while aiming to preserve salient features in the image. We show preliminary results using a genetic algorithm approach and case study examples using point source, nebula, and other images. We compare the structural similarity index (SSIM) of the approximated image with the full resolution image to evaluate result quality as well as the contribution of selected baselines. Initial results indicate that our method has the potential to preserve key features of astronomical images while reducing the data size needed for correlation. In the future, this method will provide image specific correlation processing that can reduce correlation time using an approximate set of baselines or produce full resolution images that utilize the complete set of baselines. Scientists will be able to utilize this method to decide the amount of approximation appropriate for different types of astronomical objects.

Enhancing Low-Cost Ozone Spectrometers to Measure Mesospheric Winds and Tides
Omar Alam, Cornell University (Poster)
Ground-based spectrometers have been developed to measure the concentration, velocity, and temperature of ozone in the mesosphere and lower thermosphere (MLT) using low-cost satellite television electronics to observe the 11.072 GHz spectral line of ozone. A two-channel spectrometer has been engineered to yield various performance improvements, including a doubling of the signal-to-noise ratio, improved data processing efficiency, and lower power consumption at 15 W. Following 2009 and 2012 observations of the seasonal and diurnal variations in ozone concentration near the mesopause, the ozone line was observed at an altitude near 95 km and latitude of 38 degrees north using three single-channel spectrometers located at the MIT Haystack Observatory (Westford, MA), Chelmsford High School (Chelmsford, MA), and Union College (Schenectady, NY) pointed south at 8 degrees. Observations from 2009 through 2014 are used to derive the nightly-averaged seasonal variation in meridional velocity, as well as the seasonally-averaged variation with local solar time. The results indicate a seasonal trend in which the winds at 95 km come from the north at about 10 m/s in the summer of the northern hemisphere, and from the south at about 10 m/s in the winter. Nighttime data from -5 to +5 hours local solar time show a gradual transition of the meridional wind velocity from about -20 m/s to +20 m/s. These two trends correlate with nighttime wind measurements from the Millstone Hill High-Resolution Fábry-Perot Interferometer (FPI) in Westford, MA, which uses the 557.7 nm green line nightglow from atomic oxygen centered at 95 km. The results have also been compared with average meridional winds measured with meteor radar.

Optimization of Solar Imaging Using the Murchison Widefield Array
Kirsten Baker, Carleton College (Presentation)
The Murchison Widefield Array (MWA) in Western Australia is currently the best tool available to observe Faraday rotation in the heliosphere that will improve predictions of when coronal mass ejections are going to occur. In order to further study this phenomenon, the dynamic range of solar data from the MWA must be improved to be able to accurately show the bright and highly variable radio emission from the Sun. One such improvement is an extension of the Van Vleck correction formula that corrects the 4-bit signal correlation quantization used by the MWA. This correction has shown an increase in dynamic range from 228:1 to 1425:1, or 6.25 times greater, for a particular half-second interval across three 40 kHz spectral channels. This is just the beginning of a long investigation where the ultimate goal is solar observation with a dynamic range of upwards of 100,000:1.

Machine Learning in Ionospheric Phenomena Detection Using Passive Radar
Soubhik Barari, Tufts University (Presentation)
Distributed passive radar networks are powerful sources for large amounts of ionospheric data. At the MIT Haystack Observatory, the ISIS Array (Intercepted Signals for Ionospheric Science) collects petabytes (1,000,000 GB+) of passive radar images daily. While useful for the study of E-region irregularities and other atmospheric events, such large datasets are infeasible for manual annotation and require algorithmic detection and classification. In this project, we discuss a novel statistical learning framework for computer-aided discovery in ionospheric ‘big data’. Using techniques from computer vision, image processing, and machine learning, we present a automated discovery pipeline, reporting over 95% accuracy in classifying a generated passive radar dataset of over 200 images.

A Comparison of VLBI and GPS Total Electron Content Measurements of the Ionosphere and the Effects of Geomagnetic Anomalies
Avery Bruni, University of Michigan (Poster)
Two different techniques for measuring differenced ionospheric total electron content have previously been established: Very Long Baseline Interferometry, and GPS, but they are subject to different radii of sensitivity. The goal of this research was to compare measurements of the ionosphere between the two methods, hypothesizing that they are both valid techniques for such measurements. It is conceivable that geomagnetic storms could affect the agreement of these two methods, due to the shrinking of the plasmasphere to within the range of detection shared by both, but since VLBI measures differenced TEC, it is hypothesized that the effect of a storm should largely be subtracted out of our detections. The development of a program that can compare these two methods and the results that it has yielded are described and presented in this paper.

An Empirical Model for the F1-Region Lower Transition Height from Incoherent Scatter Measurements
Zachary Hall, Boston University (Presentation)
We present the results of applying Bill Oliver’s six parameter fit for resolving the ion mass-temperature ambiguity in the F1 region of the ionosphere on hourly timescales to the entirety of the MIT Haystack dataset of Incoherent Scatter Radar experiments from 2002 to 2015. We find empirically that the transition height, z{50}, key for determining unambiguously the temperature and mass of ions in the lower transition region, reaches a local diurnal minimum between 10 and 12 local time, is maximized during summer periods, and is minimized during winter periods. We also find that the lower transition height has a significant and positive dependence on A{p} index. We present an empirical model for the lower transition height as a function of local time, day number, year, f{10.7}, and A{p} index and find that the amplitude of the annual variation of the lower transition height is 4.31 km, the amplitude of the semiannual variation is 0.51 km, the amplitude of the diurnal variation is 5.73 km, and the amplitude of the semidiurnal variation is 2.87 km. The typical mean value of the lower transition height about which these annual and diurnal variations occur for median geomagnetic and solar activity conditions is found to be 185.9 km.

GPGPU Acceleration of ISR Plasma Line Analysis and Application to Arecibo Plasma Line Striations
Natalie Hilliard, University of Wisconsin, Madison (Poster)
Weak incoherent scatter radar (ISR) scatter from naturally occuring Langmuir oscillations, or plasma lines, contain high precision information on the altitude-dependent thermal ionospheric electron density. However, analyzing this frequency-dependent scatter over a large number of radar ranges requires large computational power, especially when the goal is realtime analysis. General purpose computing on graphics processing units (GPGPU) offers immense computational speedup when compared to traditional central processing unit (CPU) calculations for highly parallelizable tasks, and it is well suited for ISR analysis. We extend a single graphics processing unit (GPU) algorithmic solution and discuss the algorithm developed. Results indicate an order-of-magnitude improvement over CPU analysis and suggest that GPGPU can achieve realtime speed for plasma line applications.

Arecibo incoherent scatter radar measurements of plasma lines are known to have sharp striations in plasma line power, which vary as a function of the plasma frequency and the aspect angle of the radar beam with respect to the Earth’s magnetic field. We explain these striations as a manifestation of a low pitch angle photo-electron population with peaks at energies of approximately 15.5, 23, 27 eV, and 50 eV, corresponding to sharp features known to be present in the photoelectron energy spectrum. Through forward modeling, we predict the locations of the amplitude striations in upshifted plasma-line measurements obtained at Arecibo for different magnetic field aspect angles.

An Updated Study of the O+-O Collision Frequency Using Corresponding FPI and ISR Thermospheric Wind Experiments at Millstone Hill
Anthony Lima, University of Colorado at Boulder (Poster)
O+-O collision frequency is an important aeronomic parameter associated with upper atmospheric momentum and energy exchanges between O+ and O. In an analysis of Fabry-Perot Interferometer (FPI) and Incoherent Scatter Radar (ISR) data, Burnside [1987] suggested a modification factor (1.7) to the traditional value of O+-O collision frequency. Determining more accurately the Burnside Factor has been the subject for many prior studies with different techniques. This study revisits the Burnside Factor by using an extended FPI and ISR dataset from Millstone Hill. The FPI data used are from an updated high-resolution instrument, which began operation in 2009. The study included data from 95 nights between 2010 and 2015 when the FPI and ISR (with both zenith and steerable antennas) were all operating. Nights with high AP were excluded, leaving 1235 data points in total. The same frequentist approach applied previously in Buonsanto et al. [1997] (using 21 experiments) yields similar right-skewed Burnside Factor distribution on this data. In this study we will discuss results derived using different statistical approaches, including median, mean, and the Bayes theorem. The latter method gives an estimate of 0.68 ± 0.02.

Scientific Data Processing on Mobile Devices
David Mascharka, Drake University (Presentation)
Scientific data acquisition in the field is often constrained by data transfer backchannels to analysis environments. Geoscientists are therefore facing practical bottlenecks with increasing sensor density and variety. Mobile devices, such as smartphones and tablets, offer promising solutions to key problems in scientific data acquisition, pre-processing, and validation by providing advanced capabilities in the field. This is due to affordable network connectivity options and the increasing computational power of mobile devices.

This contribution exemplifies a scenario faced by scientists in the field and presents the ”Mahali TEC Processing App” developed in the context of the NSF-funded Mahali project. Aimed at atmospheric science and the study of ionospheric Total Electron Content (TEC), this app is able to gather data from various dual-frequency GPS receivers. It demonstrates parsing of full-day GPS observation files on mobile devices and on-the-fly computation of vertical TEC values based on satellite ephemeris models that are obtained from NASA. Our experiments show how parallel computing on the mobile device GPU enables fast processing and visualization of up to 2 million datapoints in real-time using OpenGL. GPS receiver bias is estimated through minimum TEC approximations that can be interactively adjusted by scientists in the graphical user interface. Scientists can also perform approximate computations for ”quickviews” to reduce CPU processing time and memory consumption. In the final stage of our mobile processing pipeline, scientists can upload data to the cloud for further processing.

Analysis of the Relationship between a Change in Wind Field Curl Rate and Sea Surface Height within the Beauforte Gyre Region of the Arctic
Tyler Pelle, State University of New York, Oswego (Presentation)
Numerous interconnections exist between atmospheric, oceanic, and sea ice processes that impact the delicate climate system within the Arctic. In particular, the effect of the surface wind’s frictional drag on the large scale movement of ocean water and sea ice within the Beaufort Gyre has gained notoriety due to its perceived impact on freshwater doming and oceanic circulation systems. An analysis of the wind field curl is undertaken for the time period of 1996 to 2010 in order to determine if a negative wind curl regime occurred within this time period, which would act to increase the anticyclonic rotation (and possibly freshwater doming) of the Beaufort Gyre. Using surface wind data from the NCEP/NCAR, ECMWF Interim, and JRA-55 reanalyses, a marginal negative wind curl anomaly slope of −0.113 ±0.037 (10⁻⁶ 𝑚 𝑠⁻²𝑦𝑦⁻¹) was calculated along with insignificant wind curl trend values within this region. Additionally, SI04 autonomous ice drifting platform location data was manipulated to obtain the velocity field and power spectrum of its track. An approximate 12-hour cycle of maximum sea ice velocity is found, which is a product of the Coriolis effect; however, no strong conclusions can be made due to the preliminary nature of these findings. Future research includes a study of the sea surface height and the full power spectrum of the Arctic Ocean in order to draw more concrete conclusions.

A New Software User Interface for the Upgraded Haystack 37-meter Radio Telescope
Matthew Siebert, Cornell University (Presentation)
Recently the 37m Haystack antenna has undergone major hardware upgrades that have significantly enhanced its capabilities for radio astronomy observations. A new software user interface was developed to accommodate the new antenna and radiometer capabilities. The UI was designed for both real-time data acquisition and post-processing data pipelines. The software includes three applications that facilitate astronomical observation. The main application is a sky map of radio sources that displays important antenna status information. There is also a discrete source scan (DSS) plotting application, and an application to provide an astronomer with an idea of what is currently up in the sky. These tools give both astronomers and engineers a means to operate and collect data effectively from the 37m telescope.

Climatology of Thermospheric Temperature and Oxygen Density during 2002-2013 at Millstone Hill
Jessica Bozell, Purdue University (Presentation)
In recent years, climate change has become an area of increasing importance as researchers strive to better understand the impact of increased greenhouse gas concentrations on earth’s atmosphere. Past studies suggest that in the thermosphere and ionosphere, there is a cooling effect which results in a reduction in neutral densities and height dependent changes in electron density. The purpose of this study is to further investigate the long-term changes in the neutral atmosphere by using ground-based incoherent scatter radar (ISR) measurements of the ionosphere and thermosphere. Ion energy balance calculations can be used to estimate exospheric temperature and neutral oxygen density from the radar-measured ionospheric parameters. By using modified versions of existing codes that describe the ion energy balance equations [Nicolls et al., 2006], ionospheric data collected from the Millstone Hill ISR (42.6°N, 288.5°E) between 200 and 600 km from 2002-2013 has been used to calculate exospheric temperature and neutral oxygen density. These results are then used to create a new local empirical model that can describe the climatology of these parameters, varying with local time, season, solar and geomagnetic activities. Comparing the exospheric temperature and neutral oxygen density data measured at Millstone Hill to corresponding MSIS values, there is a possible long-term cooling trend seen in these observed thermospheric parameters at Millstone Hill. These results, based on the most recent solar cycle observations, will be extended to include more solar cycles, and a much improved understanding of the thermospheric long-term trends may be reached.

Characterizing the Jet Precession of Quasar 3C273 at 1.3mm with the Event Horizon Telescope
Michael Calzadilla, Univ. South Florida (Presentation)
The Event Horizon Telescope (EHT) is an array of millimeter-wavelength telescopes that observe the nearest supermassive black holes using the technique of very long baseline interferometry (VLBI). The EHT is uniquely capable of resolving structures on angular scales of tens of microarcseconds, corresponding to a few Schwarzschild radii around nearby black holes such as the one in our galactic center, Sgr A*. One of the goals of the EHT is to better understand relativistic outflow processes around black holes, which can be achieved due to its extremely high spatial resolution. To that end, here we present the first high-resolution VLBI observations of 3C273 at 1.3mm. We successfully detected non-zero closure phases, which indicate asymmetric structure that we then fit using simple geometric models. The orientation between model components varied over the range of years that 3C273 was observed, in agreement with multi-epoch data at lower frequencies. Our results suggest that precession can be observed even at sub-parsec scales in 3C273. Furthermore, we demonstrate that polarimetric ratios can be used for relative astrometry between flaring components and discuss the implications of that for future research.

Design and evaluation of compact antennae for ionospheric sounding
Tyler Erjavec, Ohio State University (Presentation)
Compact high frequency (HF) antennas are crucial for enabling the use of HF radar sounding for ionospheric remotely sensing using a dense network of sounders. Current ionosonde antennas are too large and expensive. In this study, we investigate two compact HF antenna designs through modeling and prototypes: a folded resistively loaded dipole, and a capacitively tuned small magnetic loop.
Both antennas were modeled using FEKO to investigate antenna efficiency and beam patterns. The folded dipole was bought off the shelf, while the compact magnetic loop prototype was built in house. In this study, we present both modeling and measurements of the antenna characteristics. We also present the first ionospheric soundings obtained using the prototype antennas.

Investigations of Hemispherical Differences in Geomagnetic Storms
Katerina Gonzales, Colorado School of Mines (Presentation)
The influence of geomagnetic storms on the total electron content (TEC) varies as a function of longitude, season, and hemisphere. None of these differences in TEC are fully understood. Using the TEC data from the ground-based GPS receiver network in the Madrigal database, we analyze the data from 2009 until 2014 in the polar regions from 65 to 90 degrees and -65 to -90 degrees. Our processing started in 2009 due to the better coverage in the GPS ground network in the southern hemisphere in this solar cycle. Case studies are selected from different seasons and longitudes to compare and contrast quiet-time TEC and storm-associated TEC in both hemispheres. We first identify a seasonal dependence of the hourly TEC by analyzing hourly averages in a three-day period around the solstices and equinoxes from 2009 to 2013. Then, we examine storm-time effects on the TEC by examining the hourly averaged TEC in a three day window around a particular storm. We investigate a hypothesis that 1900 UT and 700 UT are favorable times for storm enhanced density (SED) in the northern and southern hemispheres, respectively.

Using JVLA Observations of SiO Masers to Probe the Dynamics of an AGB star: W Hydrae
Patrick Kamieneski, Bowdoin College (Presentation)
The Asymptotic Giant Branch star W Hydrae (W Hya) is known to be a strong source of silicon monoxide (SiO) masers. We have used 2014 JVLA observations near 43 GHz to target eleven SiO lines. Those that were successfully detected include the vibrational ground state (v=0) transition for the ²⁸SiO, ²⁹SiO, and ³⁰SiO isotopologues, in addition to the v=1, 2, 3 lines for ²⁸SiO. These detections were used to look into such properties of the J = 1 – 0 maser emission region as shape, size, and intensity. The detection of rare spatially extended ground-state emission in a region located approximately 40 – 80 AU from the center of the photosphere will be discussed. Additionally, a saddle-like distribution in the velocity field for the v=1 case may help to confirm the existence of a weak bipolar outflow in W Hya. The results also indicate that the observed transitions have differing spatial distributions with respect to the star.

The Martian Climate Using HDO/H2-180
Miranda Kephart, Yale University (Presentation)
Isotopes of common molecules (especially water) are often used on Earth as a probe of climatic variations, both geographically and with time. This is possible because we have a good ‘standard’ for the abundances of various isotopes due to our large oceans. In order to obtain the same information about the Martian climate, we need to determine the ‘standard’ distribution of these isotopes on Mars. In April 2014, SMA observations of two water isotopes – HDO and H2-18O – were obtained, allowing the relative abundances of deuterium and hydrogen to be compared. The resulting D/H ratios decrease as a function of latitude, being highest at the Martian north pole and lowest in the southern hemisphere.

Connecting Stratospheric and Ionospheric Anomalies
Mary Spraggs, Western Kentucky University (Presentation)
This study investigates any relationship between lunar phases and ionospheric anomalies that appear at low latitudes concurrently with sudden stratospheric warmings (SSWs). The study utilizes World-wide GPS Receiver Network Total Electron Content (TEC) data spanning 13 years (2001-2014) and focuses on the changes in the equatorial ionization anomaly the Western hemisphere. TEC is highly variable due to the influences of solar flux, geomagnetic activity, and seasonal variation and these influences are removed by the use of model. This empirical TEC model is a combination of linear dependencies of solar flux (F10.7) and geomagnetic activity (Ap3) with a third degree polynomial dependency for day-of-year (DOY). With such dependencies removed, the remaining TEC variation could be resolved and attributed to an appropriate mechanism. Lunar phase and apside was investigated in particular, especially the new and full moon phases during perigees when tidal forcing would be most powerful. Lunar tidal forcing on planetary waves is also examined as being physically responsible for setting up conditions that may give rise to SSWs and ionospheric anomalies. Preliminary results suggest that such anomalies may be enhanced in intensity during the full or new moon and even more so during perigee by different amounts depending on whether the SSW is a major (40-60%) or minor (20-45%) event.

The Birth of Quasars
Rachel Thorp, California Institute of Technology (Presentation)
Little is known about the nature of luminous quasars with young radio emissions, yet active galactic nuclei (AGNs) play an important role in the properties of almost any large-scale structure in the universe. We take VLBA data of 90 unique, distant (1.4 < z < 3), luminous quasars with young jets and image their structures. This sample has been selected from the WISE mid-infrared survey with a preference towards the most heavily obscured sources (believed to be the youngest). By studying these objects, we attempt to better understand the nature of radio emission interactions with interstellar medium (ISM), and AGN formation and evolution.

Automated Discovery of Short Duration Solar Radio Bursts in Murchison-Widefield Array (MWA) Data
Brian Timar, University of California, Berkeley (Presentation)
Low-frequency radio observations of the Sun with the MWA have revealed a previously unknown class of weak radio events, with durations on the order of 1 second or less, and frequency widths of a few MHz. This radio phenomenon is not well-understood, and insight generation is difficult due to the large volume of data produced by the MWA at rates of several terabytes per hour. To address this situation, we developed a new approach for the detection, characterization, and classification of such events, as well as for the well-known Type III flares. Our technique consists of a pipeline of processing steps that starts with background noise estimation and subtraction. Radio events are then isolated algorithmically using region-growing techniques, wavelet decompositions, and thresholding. Physical parameter metadata for each event are then extracted and stored in a database. Scientists can query these data, filter events based on specified properties, and generate statistics and plots for exploratory studies. Our toolset is the first to empower MWA solar scientists with such computational intelligence in order to enhance their ability to interpret large numbers of short-lived events in voluminous MWA data. Computer vision approaches on solar images obtained from optical, x-ray, and infrared instruments are thus complemented by detections of phenomena in the radio frequency domain.

Development of a Low Cost Multichannel Spectrometer for the Study of Ozone in the Mesosphere
Emily True, University of Maryland College Park (Presentation)
Previously, Haystack Observatory has developed a low cost spectrometer for detecting ozone in the mesosphere using satellite TV dishes and a low noise block down converter feed (LNBF). While these spectrometers have contributed greatly to our understanding of the ozone at 100 km altitude, they require at least twelve hours to attain a significant signal-to-noise ratio (SNR). By using three dual polarization LNBFs, we are able to decrease the time to obtain a significant SNR by a factor of √6 or to about two hours. The increased sensitivity also can provide a fine enough resolution to provide data about wind speeds and the temperature of the ozone in the mesosphere. The modest cost of the system is maintained by using inexpensive digital TV tuners and demodulators. This system will enable scientists to gain continued understanding of the atmosphere at a fraction of the cost of other methods.

Designing, Simulating, and Testing the Power Subsystem for RAPID
Poornima Aggarwal, Cooper Union (Presentation)
This project is driven by the necessity to create a self-containing, reliable power subsystem for each unit in the RAPID array. RAPID seeks to create a transportable, reconfigurable, and flexible antenna array for collecting radio interferometric data from observations around the globe. The power subsystem has three main components, a photovoltaic panel to generate power, a battery to store the power, and a charge controller to regulate how the power generated is distributed between the battery and load. Many factors must be taken into consideration during the design process such as cost, efficiency and mobility of the hardware. A Python simulation program is presented to predict how the hardware will operate under different load scenarios and geographic conditions; as well as a test bed implementing the components and allowing for real time voltage, current, and solar radiation measurements to be taken. After determining which hardware would be best suited for RAPID, this project aims to develop a method for predicting the feasibility of running different experiments given the amount of solar radiation at the desired location and time of year by combining data from both the simulation and the test bed.

Volcanic Effects in the Upper Atmosphere
Anirudh Chiti, Cornell University (Presentation)
Large volcanic eruptions have a well observed impact on the lower atmosphere and climate. In the past forty years, two eruptions, El Chichon in 1982 and Pinatubo in 1991, released significant amounts of aerosols. The effects of these two volcanos have been studied in the stratosphere (10km – 50km), but not in the upper atmosphere. This project attempted to find traces of the two eruptions at altitudes of 250km to 500km through temperature trend studies. An ion temperature trend model was refined and then used to subtract solar, geomagnetic, annual, semi-annual, and correlated effects from Millstone Hill Incoherent Scatter Radar (ISR) data. After subtraction, the ion temperature residuals were studied around the years 1982 and 1991 for anomalous dips. Additionally, the model’s validity was checked by a separate model that used altitude spline fitting as opposed to median binning. The spline fitting model gave finer altitude resolution and qualitatively agreed with our model, thus showing consistency of observed trends and residual effects. The original modeling technique was then applied to the Sondrestrom and St. Santin ISR sites to validate temperature trends and volcanic effects at different locations. Then, global satellite drag measurements of electron density were analyzed for traces of volcanic activity with an updated model. Effects of the 1982 El Chichon eruption appeared to exist in all sets with relevant data (Millstone Hill, St. Santin, and satellite drag measurements), but the 1991 Pinatubo eruption was not as consistently present. Further study is needed to understand the theoretical effects of volcanic activity at those altitudes and gauge the significance of the observed temperature residuals.

Development of a Low Cost Spectrometer for the Small Radio Telescope (SRT), Very Small Radio Telescope (VSRT), and Ozone Spectrometer
Marc Higginson-Rollins, University of Kentucky (Presentation)
Several instruments used for education, outreach and scientific investigations could benefit from a low cost spectrometer. These include the Small Radio Telescope known as the “SRT”, a very small radio telescope known as the “VSRT”, and an 11 GHz Ozone spectrometer. The SRT is used to observe the Sun and the 21-cm hydrogen line. The SRTs, which until recently were available commercially, are still in operation at many universities and are used for student projects including measuring the Galactic rotation curve of our Galaxy. These instruments, which were initially primarily used to help teach students how to analyze scientific data, are now used for scientific investigations that have resulted in publications in science journals. Recently a low cost USB “dongle” for digital TV has become available. It has been adapted for use as a software defined radio by amateur radio groups. Linux-based software was developed to adapt the device to form a low cost digital spectrometer for the SRT by integrating open source code into the existing C code written for the SRT. Some challenges faced when trying to integrate the USB TV dongle into the SRT system and software will be discussed. To test the effectiveness of the USB TV Dongle based SRT several astronomical observations were made and compared to the older SRT system. These observations show promise for the device replacing older SRT systems at a fraction of the cost and effort and as a possible replacement for the VSRT and Ozone spectrometer. 

The Instrumental Effects on VLBI Polarization in Event Horizon Telescope Baselines
Michael Kosowsky, Brandeis University (Presentation)
We analyzed March 2013 230 GHz polarimetry data from Event Horizon Telescope observations in order to figure out the necessary calibration needed to account for instrumental polarization.  We used a Markov Chain Monte Carlo fitting algorithm to find the instrumental D-terms and the antenna gains with very low reduced chi-squared. Consequently, we have found very likely results for the gains of the SMT, the phased CARMA array, and a single comparison CARMA antenna. The MCMC code is able to be expanded to include other EHT stations as well.

Study of Ionosphere Total Electron Content for the Broadband Geodetic VLBI Fringe Model
Carlos Mulero-Hernandez, University of Puerto Rico, Mayaguez (Presentation)
The radio telescopes used for Geodetic Very Long Baseline Interferometry (VLBI) receive signals from distant astronomical objects to provide a measure of the Earth’s shape and variable rotation. However, the propagation of these signals through the Earth’s ionosphere and any other plasma between the radio source and the telescope introduces a systematic error in the geodetic observable. This dispersive delay has become more critical in light of the accuracy goals set forth in the VLBI2010 specifications for the VLBI Geodetic Observing System (VGOS) which are 1mm for position and 0.1 mm/yr for stability. In order to achieve such geodetic accuracy, this error must be accurately removed. In this work we present an investigation of the accuracy of the dispersive component of delay as determined by the broadband geodetic VLBI technique.  We will describe the features and implementation of a frequency-dependent forward model of this dispersive delay for VLBI.  The application of this model yields an estimate of the combined ionospheric and extraterrestrial total electron content (TEC) using a nonlinear parametric search. We assess the quality of this VLBI-based TEC estimate by comparing it with TEC values obtained using nearby GPS systems.

Passive Radar Imaging of Meteor Trails
Shayan Sohbatzadeh, University of Florida (Presentation)
I will discuss the development of single site passive radar interferometry and its application to the detection of meteor trails. Near earth space contains small pieces of matter known as meteoroids, some of which intersect the earth’s orbit and are then called meteors. The larger meteoroids produce a visible emission, a meteor. Meteors also have a plasma trail that can be detected by radar. Concepts explored in the project include passive radar, adaptive filtering, radar interferometry, and correlation. The software implemented to support the needed mathematical analysis techniques will be described. An overview of the experimental system, data collection, and the results of the radar analysis will be presented.

Daily Variations of Lower Thermospheric Tides at Middle Latitude and Their Association with Sudden Stratospheric Warming Events
Rebecca Steeves, North Carolina State University (Presentation)
Sudden Stratospheric Warming (SSW) events have been shown by both observations and model results to couple the polar stratosphere to the low latitude ionosphere. Studies have suggested that a partial driver of the connection is the amplification of tides due to the SSW that reaches maximum at mid-latitudes. This study aims to increase the understanding of the coupling processes at mid-latitudes to establish possible SSW effects on dominant tidal structures. We utilize lower thermospheric (100-130 km) data collected from the Millstone Hill Incoherent Scatter Radar (ISR) (42.6N, 288.5E) during the Northern Hemispheric winter experimental campaigns classified as either SSW events or non-SSW events. The campaign set is comprised of two SSW events, one minor and one major, along with three non-SSW events. We also examine environmental characteristics such as temperature, zonal wind, and planetary wave activity (zonal wave numbers 1 and 2) from National Center for Environmental Prediction (NCEP) data for each campaign to distinguish any noteworthy characteristics. Comparison of the campaigns concentrates on the amplitudes and phases in the zonal and meridional winds. The altitudes of analysis lie in the range between 100 km and 124 km where the dominant tides were extracted at 3 km increments. Dominant tidal structures are the 12-hour tide and 6-hour tide, indicated by the Lomb-Scargle spectral analysis. The study focuses on these tides to show differences between campaigns and daily variations. A common trend found among the campaigns, both SSW and non-SSW events, is large day-to-day variability and evidence of oscillations with periods on the order of 2-4 days. Differences in phases show the most distinction between campaign subsets, especially in the meridional component.

Design of a Stream Based Software Radar Architecture
Karl Cronburg, Bucknell University (Presentation)
Software Radar systems are crucial to the collection and analysis of data from instruments such as the Millstone Hill Incoherent Scatter Radar and the ISIS Array. The existing software radar systems used by these instruments are tightly coupled to their computing infrastructure and relatively inflexible in their configuration. Modern software infrastructure for distributed messaging, serialization, and elastic computing can be exploited to enable a more flexible and scalable approach. Radar instruments can stream data onto shared processing networks which scale their response by employing additional computers on demand. Clean boundaries are created using a simple interface definition language using YAML (yet another markup language) which allow for automated serialization and transport of software radar data, metadata, and control information. These definitions may be used directly from revision control and are used to dynamically generate software object definitions. A modern and ‘broker-less’ messaging infrastructure (ZeroMQ) is used to provide a range of messaging models (publish-subscribe, request-reply, etc) for object transport. Automated serialization of objects is supported using YAML, MessagePack, and HDF5 with optional compression using gzip. The application of these components is discussed in terms of a prototype focused on passive radar signal processing. The structure of this distributed signal processing application illustrates the use of many of the capabilities of the new architectural approach and components.

Development of a New Generation Small Radio Telescope (SRT)
Dustin Johnson, Dalhousie University (Presentation)
The original Small Radio Telescope (SRT) developed at Haystack Observatory is no longer in production and has become obsolete due to technological advances. We describe the design of the new SRT, its capabilities, and improvements made over the old. Several radio frequency interference (RFI) problems were encountered and addressed. Astronomical observations were taken to examine the performance of the new SRT. Some software was developed for the new SRT and thorough documentation and instructions on its assembly were prepared.

Development of a Pattern Simulator for Benchmarking a Near-field Holographic Image Processor
Kathryn Martin, North Georgia College & State University (Presentation)
Deformations of the reflector optics comprising a radio telescope can introduce station position errors that are significant in the context of VLBI2010. Radio holographic imaging is a technique that can be utilized to detect such deformations. In experiments involving large reflector antennas at relatively high frequencies, geosynchronous satellites are observed to conduct far-field radio holography since the stand-off ranges satisfy the far-field requirement. However, these sources are relatively fixed with respect to the radio telescope and this limitation does not facilitate the ability to characterize the deformations over the telescope’s full field-of-view. The near-field holographic imaging technique overcomes this limitation of the satellite-based far-field technique since the source is under the control of the observer and may be placed in close proximity to the radio telescope in question. Additional complexities arise in this near-field scenario but these considerations have been addressed in the literature. In this report, a near-field antenna pattern simulator was developed to facilitate testing of a near-field holographic image processor. The results of this simulator have been compared against independent expectations to validate the simulator.

Low Cost GPS Synchronization for Distributed Instrument Arrays
Gavin McCauley, Univeristy of Massachusetts, Boston (Presentation)
Distributed instrument systems require a long-term, stabilized clock signal. Achieving such a signal often requires expensive tools, but now the coherence module at MIT Haystack aims to significantly lower that cost by using GPS synchronizing and a newly developed Analog Devices chip for generating such clock signals. The coherence module’s clock signal has been compared to an existing commercial solution’s, including an application of the Intercepted Signals for Ionospheric Sciences (ISIS) arrays at MIT Haystack and Dartmouth.

Advanced Digital Receiver for Distributed Instrument Arrays
Patrick Smith, Unversity of Florida (Presentation)
Field Programmable Gate Arrays (FPGAs) are emerging as an appealing option in modern software digital receiver design. Recent advances in FPGA technology has resulted in powerful, reconfigurable instruments at lower costs than previously available. This enables the development of more ideal and cost-efficient software defined radios. Additionally, modern design software provides users a simpler method of programming the FPGA while allowing for more reconfigurability than ever before. We developed a tool that facilitates communication between the FPGA and a temperature sensor on the analog-to-digital converter through the FMC port using the I2C protocol. The data is then sent to the central computer via the JTAG port for analysis. We will describe the design and discuss its implementation using the Virtex 6 ML605 platform and the 4DSP FMC104 analog-to-digital converter. We will follow by briefly mentioning some of the problems encountered and conclude with a discussion about future research to expand on our findings.

Characterizing Planetary Wave Signature in the Ionosphere
Jonathan Wurtz, Unversity of New Hampshire (Presentation)
Planetary waves are large-scale structures in the upper atmosphere that encompass the entire earth. In this project, a large data set of TEC (Total Electron Content) values derived from a global network of differential GPS receivers was used to investigate planetary wave signatures and geophysical drivers through various methods. Several types of derived data sets were developed, along with easy-to-use tools to manipulate and analyze the data. This report will outline the work done with developing those data sets and tools, with an emphasis on showcasing some of the results obtained.

Imaging Mira’s Masers
Rachel Zizza, Wellesley College (Presentation)
Simultaneous observations of Mira’s SiO (43 GHz), H2O (22 GHz), and OH (1665 MHz) masing regions were made for six epochs (2004-2005) with the VLA. The data were then imaged to provide information on the maser activity in the form of channel maps, total intensity (moment) maps, spot maps, and spectral line profiles. SiO and H2O masers were detected at every epoch, although the OH maser was not seen at all. Spot maps of the SiO masing region show a small area of maser features moving away from the star at about 21 km/s- a high proper motion feature which may be the result of outflow from Mira. In addition, SiO and H2O moment 0 maps from the same epoch were combined into one overlay map of their relative position and sizes. This is the first simultaneous imaging of the SiO and H2O masers that has ever been produced. From this map, the SiO masing region was found to be about 7.5 AU in diameter, and the H2O masing region 21.4 AU in diameter. The H2O maser emission also reached a maximum flux density of ~12.5 Jy, which is more than twice the 5 Jy maxima reported in other independent observations of Mira. This talk presents results that confirm previously reported characteristics of Mira’s maser emission, as well as provide valuable information for the constraint of maser emission models in evolved stars.

Development of the HART Solar Image Simulator
Mark Benjamin, Princeton University (Presentation)
As the Murchison Widefield Array (MWA) becomes fully operational, new data on low-frequency (<300 MHz) radio emissions from the Sun are expected. Low frequency radio rays suffer significant refraction and scattering in the corona, hence the need for simulated images of the sun exhibiting various features (coronal streamers etc.) obtained through ray tracing. The HART framework is intended to be a reliable numerical tool for image interpretation. In this work we describe significant improvements made on HART, which greatly enlarged its usability, speed, and provided new scientific opportunities. A GUI has been created. The computations were parallelized, first on CPU kernels, and eventually using GPU. A coronal streamer model was implemented. The Stokes parameters are computed for each ray. These improvements make HART a useful tool in various fields of solar science.

Antenna and Amplifier Modeling for High-Accuracy Calibration of Radio Data
Delani Cele, Ithaca College (Presentation)
The Epoch of Reionization is a defining moment in the history of the universe. Information about this transition period is contained in the 21cm line of neutral hydrogen in the intergalactic medium for redshift between 6 and 27 which corresponds to frequencies between 50 and 200 MHz. This summer improvements were made to the calibration of the Experiment to Detect the Global EoR Step (EDGES) which uses a radio antenna and spectrometer to look for the expected 21-cm line signature during reionization in the sky noise spectrum. Work included measurements of a balun’s s-parameters and the antenna impedance. In order to test the new calibration method, measurements were made of the sky brightness temperature from 50 to 100 MHz at West Fork, ME. A temperature spectral index of 2.51 +/- 05 was derived from the data by fitting a power law model to the calibrated sky noise spectrum.

Global Mean Total Electron Content Behavior in Periods of High Geomagnetic Activity
Aaron Fienberg, Earlham College (Presentation)
The 24-hour global mean Total Electron Content (TEC) varies significantly on periods as short as two to three days. Analyses of ground based GPS receiver measurements, CHAMP satellite GPS receiver measurements, and Jason-1 altimeter measurements yield consistent pictures of highly structured changes in the global mean TEC. In particular, we have focused on three time periods of high geomagnetic activity: October through November, 2003, November, 2004, and May through June, 2005. During these time periods, rapid changes in the global mean TEC appear related to disturbances in the DST index, changes in the solar wind speed, and spikes in the solar wind density. Comparison of CHAMP data (measurements of TEC above approximately 400 kilometers altitude) and ground based data reveals a correlation between the DST index and the proportion of TEC that is below CHAMP. This correlation suggests that DST related global enhancements are most significant above 400 kilometers.

Extreme Ultraviolet Radiation Flux Changes and Electron Density Enhancement During Solar Flares
Timothy Kelley, Rensselaer Polytechnic Institute (Presentation)
Solar flares induce sudden changes in X-ray irradiance and EUV flux. The possibility of a correlation between these changes and the daytime global value of total electron content (TEC) is investigated through the use of data from the GPS, SOHO, and GOES satellites. The Millstone Hill Incoherent Scatter Radar (ISR) is used to investigate the altitude stratification of the flare induced TEC enhancement. A study is conducted for the months of October 2002 and September 2005 as they had 329 and 114 flares, respectively. The amount of TEC enhancement due to a solar flare is found to be dependent on solar activity, solar flare strength, and the background TEC. On average, October 2002 had solar flares of less strength and higher solar activity. Flare effects were more evident in September 2005 which had on average, a small background TEC (10-15 TECu) and prominent (~2 TECu) TEC enhancements. In addition, a high and positive correlation between X-ray irradiance and EUV flux was seen during solar flare events. Through the comparison of the different data sets, it is found that the majority of the TEC enhancement is in the E and F regions (100-150 km) which corresponds to the portion of the ionosphere ionized by EUV radiation.

Ionospheric Radar Experiment Scenario Modeling
Natalie Larson, Vanderbilt University (Presentation)
MIT Haystack’s Atmospheric Sciences Group has for nearly 50 years operated the Millstone Hill upper atmospheric radar, focused on studies of the near-Earth space environment. The radar is a complex system, which can pose a challenge for experiment design. The aim of this project was to build a graphical user interface to allow a scientist to easily design and model scenarios of experiment flow through the Millstone Hill radar experiment chain. This end was achieved by creating an interface that allows a user to draw a state chart and convert the drawing into a parameter file that can then be converted into python code for controlling the radar.

GPU Based Polyphase Filter Banks for VLBI
Mark McCurry, Clarkson University (Presentation)
This project presents the evaluation of the use of a graphics processor for realtime radio astronomy DSP (Digital Signal Processing) within VLBI (Very Long Baseline Interferometry). A Polyphase Filter Bank (PFB) was implemented in a prototype application to convert external ADC input into channelized frequency streams. This system was tested with a 32 channel pfb, 8 bit samples, and 8 taps/channel. With a prototype system, 512 Mega-samples/second could be easily processed and 890 Mega-samples/second is possible. Instruction throughput is the current limitation, so a modest increase in the graphics card’s processing speed will permit the desired speed of 1024 Mega-samples/second. This makes GPUs an interesting candidate for a cost effective upgrade as both software and hardware systems progress.

High Latitude Ion Temperature Responses in the Lower and Upper Thermosphere During Sudden Stratospheric Warming Events
Catherine Miller, Embry-Riddle Aeronautical University (Presentation)
We analyzed ion temperature responses in the lower and upper thermosphere to sudden stratospheric warmings (SSWs) that occurred in January 2008 and January 2009. Ion temperatures were obtained with the Sondrestrom Incoherent Scatter Radar (67N, 51W). The SSW of January 2008 was a vortex displacement event, with Sondrestrom ISR probing the ionosphere above a cold cell in the stratosphere during the peak of the warming event. The SSW of January 2009 was a vortex split event, and the radar obtained measurements above the hot cell in the stratosphere. Despite differing local stratospheric conditions, signatures of cooling in the evening hours at 150-300km were found during the peaks of both events. To differentiate ion temperature variations caused by the SSW from variations caused by geomagnetic activity, ion temperatures from geomagnetically quiet dates from several weeks before the events were used as baselines. The Sondrestrom local ionospheric model was used to examine expected ion temperature responses to seasonal variations and geomagnetic activity. The magnitude of cooling observed during both events exceeded the variations predicted by the model. Ion temperatures observed in the evening hours of the January 2008 event at 150-300km were considerably cooler than baseline ion temperatures despite increased geomagnetic activity during the event. During daytime hours of the events, ion temperatures varied slightly from the baselines; some stronger daytime variations were observed, but no strong conclusions could be made due to fluctuations caused by geomagnetic activity.

Parallel Processing and the Madrigal Database
David Packard, Colorado State University (Presentation)
The Madrigal database is used throughout the atmospheric science community for storing and accessing archival and real time data. The speed of the database can be improved by decreasing the computation time of parameters derived from measured data. Infrastructure for passing the computations to a GPU, to be run in parallel, should decrease this computation time. This infrastructure, written in C, has been added to Madrigal via the use of NVIDIA’s CUDA. The infrastructure stores data for computations when they were previously calculated serially, dynamically appends vital record, cycle and type information, then dispatches all computations for a given method to be done at one time on the GPU. After these computations are completed, the data is written back into the Madrigal data structures, making it possible to run any pure c derivation method in parallel. This provides the potential to greatly reduce the computation time of Madrigal derived parameters.

36 GHz Methanol Masers
Hannah Seyb, Guilford College (Presentation)
Class I methanol masers are usually located in shocked environments near star forming regions. Due to limitations in instrumentation Class I masers are not as well studied as their Class II counterparts. Recent upgrades in the EVLA have allowed for the observation of the 36 GHz methanol transition that results in a bright maser emission. We mapped the 36 GHz masers in 12 star forming regions and then compared them to other Class I transitions, including the 44 GHz transition. In some sources there was complete agreement in the distribution of the masers with the 36 GHz occurring at the same locations as the 44 GHz masers. Other sources displayed no correlation between the two, where the 36 and 44 GHz masers were tracing different conditions. Numerous sources showed an intermediate level of correlation where there was some spatial overlap between these two Class I methanol transitions. In the source G10.6-0.4 the 36 GHz masers were found to be located along the edge of an outflow in areas of high density methanol gas. It will be important to analyze theses results in the context of the thermal molecular environment of the masers in order to verify various models which describe the dependency on temperature, density, and column density of the Class I methanol masers.

Microcontroller Framework for Radar Module Control
Elias Wilken-Resman, University of Minnesota (Presentation)
A GPS-based timing and synchronization system has been designed at the MIT Haystack Observatory. We have been developing a modular, microcontroller-based framework that can be used to support this and other applications. We have successfully implemented browser-based network configuration and control, as well as USB transfers from host microcontrollers to various devices. The framework is designed for multipurpose use and expansion; many other uses in distributed radar systems are envisioned.

Wideband Radio Tuner for Geospace Science Applications
Peter Anderson, SUNY Oneonta (Presentation)
Much of the research on the Geospace Environment has been done using receivers to examine signals from ground and satellite based beacons. These receivers are often coupled with costly analog components to increase the signal strength and filter out Radio Frequency Interference (RFI). We will describe the production of a generic wideband tuner that could be mass-produced which will in turn cut overall receiver costs. Agilent Genesys RF simulation software allowed us to evaluate several designs and component combinations. After optimization in software we implemented a hardware prototype. We will describe the design of our simulation and hardware prototype and the resulting performance characteristics.

Advanced Digital Receiver for Distributed Instrument Arrays
Ross Daly, Carnegie Mellon University (Presentation)
Digital down converters (DDCs) are an essential part of a modern software radio receiver. Recently, Field Programmable Gate Array (FPGA) technology has advanced to the point where it is now possible to create low cost per channel DDCs within a FPGA. Furthermore, Simulink using Xilinx’s System Generator for DSP provides a more user-friendly and time efficient way to program the FPGA compared to direct hardware language coding. We created a rate programmable DDC in Simulink and conducted simulations for RF signals up to 160 MHz based on variables such as filter coefficients, gain, bandwidth and input sources. We will describe results using both simulations and hardware co-simulations and will discuss future work needed to process real RF signals in the field.

Adaptive GPU-Accelerated Software Satellite Beacon Processing for Geospace Environmental Sensing
John Grasel, Harvey Mudd College (Poster)
Radio beacons on satellites can be used in conjunction with ground receivers to study the ionosphere. The flexibility of new wideband tuners and digital receiver platforms requires a modular, adaptable software chain to optimally process and interpret beacon overflight data. A python-based system was developed to track the beacon, filter noise, and convert the signal to baseband. The slow but intrinsically parallel nature of the process led to large performance gains when methods were ported to the Graphical Processing Unit (GPU) using a python wrapper of NVIDIA’s CUDA programming language. The presentation will discuss methodologies to port algorithms to GPU execution as well as show results for representative VHF/UHF beacon overflights in the Westford, MA vicinity.

Relationship between Stratospheric and Ionospheric Disturbances
Vicki Hsu, University of Colorado at Boulder (Presentation)
The ionosphere, located 80 km and above in the Earth’s atmosphere, has intrigued and puzzled scientists for years. Ionospheric variability impacts a variety of communication and navigation systems. Although the primary drivers of ionospheric variability are relatively well understood, the effects of the lower atmosphere onto the ionosphere remain elusive. Due to the current deep solar minimum, new studies have shown promising results that shed light on the coupling of the ionosphere to processes from below. This presentation focuses on the sudden stratospheric warming (SSW) event that occurred in January 2010, and presents the results obtained from the Millstone Hill Incoherent Scatter Radar (ISR). Studying the 2010 SSW event will provide more insight into the interactions between the lower and upper atmosphere, and recognizing their connection is essential in understanding and forecasting the geospace environment.

Investigating a Type III Solar Burst with the MWA Prototype
Rachel Kennedy, University of California, Berkeley (Presentation)
The Murchison Widefield Array is an ambitious endeavor in remote Western Australia to install a 512-element radio interferometer with unprecedented imaging capabilities at low (80-300 MHz) radio frequencies. The current prototype comprises 32 dipole-antenna tiles which have begun to collect preliminary data on the sun. This talk will focus on a Type III solar burst that was recorded by the array on March 29, 2010, as well as the quiescent periods before and after the burst. In my investigation, I took advantage of the unique spatial, spectral and temporal resolution of the MWA to study the changing profiles of flux, frequency and polarization over time. Finally, I imaged the burst sequentially and concluded that some of the unexpected behavior of the sun at these wavelengths may be the result of a solar active region that has been observed in multiple bands near the center of the disk.

Conditioning a Cryogenic Sapphire Oscillator with GPS Reference Presenter
Tao Mai, Columbia University (Presentation)
Hydrogen masers have been widely used as frequency references for Very Long Base-line Interferometry (VLBI). As an alternative, Cryogenic sapphire oscillators (CSO) have stability superior to hydrogen masers on time scales shorter than tens of seconds, which makes them potentially better frequency standards for high frequency VLBI. But CSO’s are prone to frequency drifting on longer time scales, and they need to be disciplined by an external time standard. This report discusses improvement of the long term stability of a specific CSO by conditioning it with GPS reference.

Mapping Class I Methanol Masers in the DR21 Region
Talitha Muehlbrad, Texas Lutheran University (Poster)
We present the first interferometric data of methanol masers in the 4-1→30 E transition at 36GHz in DR21OH, DR21W, and DR21N. In the two sources which have other published maps of other methanol maser transitions, our data are in agreement with these other transitions. Masers found in DR21OH match the outflow pattern seen in other transitions, and those found in DR21W are in agreement with the line of masers found in other transitions. DR21N shows a line of bright redshifted masers near a scattering of low-intensity blueshifted masers. A very large magnetic field was detected in DR21W which may be evidence for a different mechanism of maser pumping than commonly assumed for Class I masers.

Looking Inwards: Holographic Imaging of Parabolic Antenna Apertures
Rachel Nancollas, Franklin W. Olin College of Engineering (Presentation)
The sensitivity of radio telescopes is strongly dependent on the antenna’s near-field characteristics, which can be studied using holographic imaging. Here we discuss a method for producing holographic images of the 5 meter MV3 antenna at Goddard Geophysical and Astronomical Observatory (GGAO) using a data collection system that was developed for the VLBI2010 broadband receiver. Our image processing hinges on the Fourier relationship between the antenna’s far-field pattern and the electric-field distribution in the aperture of the primary reflector (i.e. the near-field distribution). The results of our imaging suggest that MV3’s subreflector is over-illuminated because we observe significant ripple in the near-field distribution. More importantly, the images generated from MV3 holography collections suggest that our imaging technique can accurately create maps of the antenna surface. In the future, this holography software will be used to image the aperture of the new 12 meter VLBI dish currently under construction at GGAO. 

A Statistical Analysis of Ionospheric Pedersen Conductivity
Farzan Beroz, Duke University (Presentation)
We will discuss the results of an expanded statistical study on regions of fast flowing plasma in the ionosphere called Sub-Auroral Polarization Streams (SAPS). These events have been sampled many times by the Millstone Hill incoherent scatter radar, and are a consequence of electromagnetic coupling between the upper atmosphere and the overlying magnetosphere. A better understanding of the properties of SAPS is essential to understanding the Sun-Earth system. We will describe efforts to organize Millstone Hill radar measurements of SAPS to examine the events. In particular, our work has produced a Python class-based software data structure that will facilitate future analysis work and that easily allows new parameters to be added. We will describe statistical analysis results of ionospheric Pedersen conductivity, an important quantity for determining the dynamics of SAPS event behavior as a function of season and time of day.

Effect of Sudden Stratospheric Warming Event on Low- and Mid-Latitude Ionospheric Parameters as simulated in the TIMEGCM model
Allyson Clark, Pennsylvania State University (Presentation)
Ionospheric parameters including temperature, vertical drift, and electron density of the TIME-GCM model were analyzed in this study. The investigation was conducted using model data corresponding to mid- and lower-latitudes during the sudden stratospheric warming event of January 2008. Vertical temperature profiles showed a distinct wave pattern, decreased temperatures and smaller changes in time during the SSW event. The structure of vertical drift profiles were similar between a day during the SSW event and a day without an event. There were similar periodic structures in electron density when comparing profiles during and prior to the SSW event. Decreases in electron density during the SSW event were also seen. Given the model’s realistic reproduction of atmospheric conditions in the mid and lower latitudes, the investigation was then focused on a series of large changes in total electron content over the time period. Total electron content was discovered to have a linear dependence on AP Index and had little dependence on solar flux at the mid-latitudes during December to February between 9 and 15 local time, including days during the SSW event.

HI as a Tracer of Circumstellar Envelopes
Marshall Johnson, Wesleyan University (Presentation)
Asymptotic giant branch (AGB) stars are a near-final stage of evolution for approximately solar-mass stars. These stars undergo mass loss, forming circumstellar envelopes of scale ~1 pc and mass ~10⁻³ M_Sun. These envelopes have previously been detected in a variety of tracers (e.g. CO, SiO, silicate dust). The HI 21-cm line offers a number of advantages for observing these envelopes, such as the ability to detect the envelope at large distances from the star. High-resolution HI observations were taken of three AGBs (X Her, R Peg, and Y UMa) using the Very Large Array. Additionally, low-resolution observations of X Her were made using the Green Bank Telescope.  The data indicate that circumstellar envelope morphologies are more complex and varied than previously suspected.

Pioneering Observations with the Murchison Widefield Array: Searching for Radio Transients
Gregory McGlynn, Northwestern University (Presentation)
The Murchison Widefield Array, currently under construction in Western Australia, will be a wide-field radio telescope operating in a relatively unexplored frequency range. These properties give the MWA a good chance to detect previously unnoticed transient radio signals from high-energy astrophysical events. Transient radio signals will provide clues about the physics of these energetic astrophysical processes, and may reveal previously unknown processes at work in the cosmos. This summer I worked on the All Sky Monitor, a piece of software that will analyze MWA data in real time to detect transient signals. I will present the results of some simulations to test the effectiveness of the transient-detection algorithms and the sensitivity of the MWA to transient signals.

Pioneering Science with the MWA: Observing the Quiet Sun
Shane Rightley, University of Arizona (Presentation)
The Murchison Widefield Array (MWA) is a 512 element interferometric array designed to operate at radio frequencies from 80 to 300 MHz. It is under construction in the Murchison region of Western Australia, and will feature 512 electronically pointed tiles, each consisting of 16 phased dipole antennas.  There is presently a 32 tile (32T) prototype of the array setup on site that is being used to demonstrate the validity of the hardware and software designs, as well as to establish some early science results.  One of several targeted science objectives for the MWA is the study of the Sun and the inner heliosphere.  The MWA 32T is thus well matched for the study of the solar corona, with the instrument’s frequency range corresponding to the local plasma frequency in the corona at heights above the photosphere between approximately 0.1 and 1 solar radii.  We present flux calibrated images of the Sun produced by the MWA 32T at 5 frequencies between 85 and 235 MHz.  Results for total flux densities and radial brightness temperature profiles are compared to theoretical expectations as well as established results and are found to be in fairly good agreement. It is concluded that the MWA 32T is capable of producing valid and useful data and that further analysis of the solar images may yield information about the large scale electron temperature in the Sun’s corona.
 

1.3 mm VLBI study of M87
David Schenck, University of Arizona (Presentation)
The radio galaxy M87 is the largest galaxy in the Virgo cluster located about 16 Mpc away. At its center, M87 is believed to harbour a super massive black hole whose mass estimate was recently doubled to a value of 6.5*10⁹ solar masses. This black hole is the engine for a relativistic jet that extends for kiloparsecs from its base, though the specific mechanism for the jet’s formation and structure are unknown. M87 is one of only two radio galaxies to be detected in very-high-energy (VHE) gamma-rays emission. This emission is variable on timescales as low as two days and is believed to originate close to the black hole’s event horizon. Many models have been proposed to explain this emission. Using telescopes in Hawaii, California, and Arizona to conduct a VLBI observation at 1.3 mm (230 GHz), a strict limit was set on the size of the emitting region. The spatial scales predicted by several models were compared to this value to check the validity of the models.

Investigation of a Thermo-electrically Cooled UHF Radar Amplifier Module
Michael Shusta, University of Massachusetts – Amherst (Poster)
In radio instrumentation, the system noise level of a receiver is dominated by the noise added by the first stage after the antenna: the low-noise amplifier (LNA) . It sets the performance of the receiver in terms of gain, noise figure, stability, and dynamic range. Radar operators working in astronomy and atmospheric science who desire very low system temperatures cool their front-end LNA with cryogenic apparatus. The primary motivation of this engineering project is to achieve a more modest performance gain with simpler, cheaper, and lower-maintenance means: thermoelectric cooling. Thermal simulations of a UHF front end module were performed in the COMSOL Multiphysics environment, which show LNA cooling to 200K. A vacuum housing design and thermal analysis are shown, to be implemented in the Millstone Hill Incoherent Scatter Radar at MIT Haystack Observatory.

Development of an Optimized Antenna for an Ozone Spectrometer
Sai Tenneti, University of Massachusetts – Amherst (Presentation)
The goal of this project was to optimize the performance of a spectrometer at Haystack that measures the amount of ozone in the mesosphere. This required searching and testing for compact, inexpensive low noise block converters (LNBs) that can perform efficiently in the X-band of the electromagnetic spectrum. Various devices were tested such as the Fortec FSKUVN 0.2 dB, Invacom SNF-031 0.3 dB Horn, Invacom SNF-031 0.3 dB C120 flange, and the Smart 0.1 dB. Software was used to estimate the “sky noise” as a function of azimuth and elevation, and in turn was used to calculate the antenna response. Numerous calibration techniques were used to obtain accurate values for the noise figure, such as the use of various absorbers to measure the “Y-factor”, liquid nitrogen calibration, and also calibration with a fluorescent lamp that periodically turns on and off. Some possible solutions to reduce spillover from the ground and further optimize the antenna performance, were also tested.

Observing the Earth’s Topside Ionosphere with Multiple Atmospheric Instruments
Gabrielle Tepp, Michigan State University (Presentation)
How can you determine the amount of plasma in the upper ionosphere?  Using incoherent scatter radars (ISR), one can only determine the total electron content (TEC) up to an altitude of around 500-800 km.  GPS satellites, on the other hand, orbit the Earth some 20,000 km above the ground and can be used to determine the TEC up to that height.  By comparing the data from the two types of instruments, the TEC of the upper ionosphere can be determined.  Other than the daily cycle of variation, the amount of plasma changes depending on location and time of year as well as other factors such as solar storms.  In this project, the plasma contents for two time periods from four different radars with numerous GPS receivers are compared.  The time periods are for 1-6 March 2007 and 9-13 July 2008.  The radars used are AMISR in Poker Flat, AK; Millstone Hill in Westford, MA; Sondrestrom in Kangerlussuaq, Greenland; and the EISCAT Svalbard ISR in  Longyearbyen, Svalbard.  From the data, it was found that the GPS data processing still leads to biases.  Different elevations and azimuths for the instruments were compared.