Bulletin of the American Physical Society
2021 Virtual Conference for Undergraduate Women in Physics
Friday–Sunday, January 22–24, 2021; Virtual
Session U12: Astrophysics and Cosmology VIInteractive Live
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Chair: Rebecca Rapp, Carnegie Mellon Univ |
Sunday, January 24, 2021 12:00PM - 12:10PM |
U12.00001: Merger Signatures in Cold Quasars Casey Carlile, Allison Kirkpatrick, Eilat Glikman Cold Quasars ($\rm Lx > 10^{44}$ erg/s, $\rm S_{250} > 30$ mJy) are a recently discovered, extremely rare galaxy. They are luminous in both the X-ray and infrared wavelengths and can have up to seven times as much star formation as normal quasars. They are predicted to be a step in the progression between the starburst galaxies that have undergone a recent galaxy merger and blue, unobscured quasars. However, they mainly look like blue point sources in Sloan Digital Sky Survey imaging. In order to test whether Cold Quasars are produced by mergers, we examine the deep images from the Hyper Suprime-Cam of the Subaru Telescope. We fit multiple models using GALFIT to look for double nuclei or asymmetrical residuals. We find that Cold Quasars are more asymmetrical than a control sample of unobscured, blue quasars, supporting a scenario in which the Cold Quasar phase occurs at the very end of a merger, directly preceding blow out and quenching. [Preview Abstract] |
Sunday, January 24, 2021 12:10PM - 12:20PM |
U12.00002: Fred Young Submillimeter Telescope Field of View Rotation: Visualizing Image Plane Rotation on the Sky Bailey Filer, Thomas Nikola, Gordon Stacey, Christopher Rooney, Cody Lamarche, Catie Bell, Mahiro Abe h $-abstract-$\backslash $pardThe Fred Young Submillimeter Telescope (previously CCAT-Prime), an upcoming observatory which will be placed in Northern Chile in 2021. It is designed for sub-millimeter to millimeter wavelengths with a 6 meter diameter telescope. The whole structure turns 360 degrees at its base, while the telescope itself, essentially a massive box containing mirrors, tilts from 0 to 90 degrees. The curvature of the mirrors causes a field of view rotation at the focus directly proportional to the angle at which the sky is being observed. This rotation will be disruptive to results, necessitating visualization code which will demonstrate the rotation in order to account for it when taking data. Python was learned and utilized over an eight week period, and this visualization code was created. The process involved plotting a simple circle in Right Ascension vs. Declination coordinates. This plot, including each coordinate on this circle was then transformed into Altitude vs. Azimuth coordinates. Finally, matrix multiplication was utilized to rotate this circle based on an observation angle and location on the earth which were both pre-determined. The next steps are accounting for this rotation in the program. This code will be built off in order to take measurements pertaining to the age of distant galaxies and many other projects in the future. $\backslash $pard/abstract-$\backslash $\tex [Preview Abstract] |
Sunday, January 24, 2021 12:20PM - 12:30PM |
U12.00003: Finding Transient Artifacts with Deep Learning in the Dark Energy Survey Pavani Jairam, Jiayue Xu, Rebecca Bell, Kevin Liang, Michael Troxel, Bruno Sanchez, Daniel Scolnic, Christopher Walter Cosmological surveys increasingly rely on deeper astronomical imaging, including tens to hundreds of single-epoch images in coadds. These images contain many non-cosmological transient artifacts, such as cosmic rays, satellites, and asteroids, which can hinder astronomers' ability to accurately infer a representative cosmological object sample. The Dark Energy Survey (DES) Year 3 results relied on manual visual inspection by volunteers of all deep field coadd images to detect and mask residual transient artifacts. As the quantity of data of cosmological surveys increase, machine learning techniques provide an opportunity to supplement and assist these time-consuming stages of data processing. Through the utilization of deep learning architectures trained on DES deep field image data masked by volunteers, we develop methods for both patch-based classification and direct localized detection of transient artifacts. We find the artifact detection labels by volunteers to have a number of errors, so we introduce a human-in-the-loop relabeling step to correct these mislabels. The models reach high levels of precision and recall and show promising use for automated artifact detection in DES Year 6 deep coadd image stacks and other cosmological surveys. [Preview Abstract] |
Sunday, January 24, 2021 12:30PM - 12:40PM |
U12.00004: Radiogenic Heating and the Thermal Evolution of Earth-like Exoplanets Alysa Rogers, Jisheng Zhang, Leslie Rogers Radiogenic heating is an important component of the thermal evolution and geodynamo of a planet; thorium and uranium alone account for 30-50\% of the Earth's internal heat budget. Most previous models of rocky planet interiors have used chondritic values for radiogenic heating, which doesn't take into account variance in abundance due to planet formation, partitioning of radioactive elements into the core, or variation of host star photospheric abundances. This project explores the effects that different radioactive abundances in the mantle have on the thermal evolution of a planet by expanding a previous model of rocky planets. We found that the upper bound of radioactive abundances significantly prolonged the solidification time of the core, explained by greater flux as compared to the lower bound. Modelling the effects that variations in radioactive element abundances have on rocky planets' thermal evolution could allow us to estimate planet compositions from observations of planetary magnetic fields. [Preview Abstract] |
Sunday, January 24, 2021 12:40PM - 12:50PM |
U12.00005: Color Variations on Asteroid (101955) Bennu Antara Sen, Beth Clark ct- NASA's OSIRIS-REx is a sample return mission to near-Earth B-type [1] asteroid (101955) Bennu [2]. Spectral variations on Bennu are subtle and associated with albedo [3]. We seek to classify the causes behind these spectral variations. By comparing the VIS-NIR spectral parameters of lab analogs [4] to those of Bennu, we find that decreasing grain size leads to spectral reddening and brightening [5]. However, studies predict that solar wind bombardment of organics (confirmed to be found on Bennu [6]) leads to spectral reddening, darkening and flattening [7] along with an upturn in UV albedo [8] -- all of which are detected on Bennu [9--11]. We thus infer that solar wind is a likely surface maturation process on Bennu, working against grain size effects. References [1] Clark, B.E. et al. (2011), \textit{Icarus }\textbf{216}(2), 462--475. [2] Lauretta, D.S. et al. (2017), \textit{Space Science Reviews }\textbf{212}(1-2), 925--984. [3] Clark, B.E. et al. (2019), \textit{EPSC }\textbf{2019}, EPSC--DPS2019. [4] Cloutis, E.A. et al. (2020), \textit{EPSC }\textbf{2020}, p. 975. [5] Sen, A. et al. (in review), \textit{Meteoritics {\&} Planetary Science}. [6] Simon, A.A. et al. (2020), \textit{Science}, \textbf{370}, eabc3522. [7] Moroz, L. et al. (1998), \textit{Icarus }\textbf{134}(2), 253--268. [8] Brunetto, R. et al. (2015), \textit{Asteroids IV, }597--616. [9] Fornasier, S. (2020), Astronomy {\&} Astrophysics, 644, A142. [10] Neumann, G. et al. (2020), LPS LI, (2326), 2032. [11] Hendrix, A.R. {\&} Vilas, F. (2019), \textit{Geophysical Research Letters }\textbf{46}(24), 14307--14317. [Preview Abstract] |
Sunday, January 24, 2021 12:50PM - 1:00PM |
U12.00006: GS 2000+25: The Least Luminous Black Hole X-ray Binary Jennifer Rodriguez, Ryan Urquhart, Richard Plotkin, Teresa Panurach, Laura Chomiuk, Jay Strader, James Miller-Jones, Elena Gallo, Gregory Sivakoff We report new, strictly simultaneous radio and X-ray observations of the nearby stellar-mass black hole X-ray binary GS~2000+25 in its quiescent state. In deep \emph{Chandra} observations we detect the system at a faint X-ray luminosity of $L_X = 1.1^{+1.0}_{-0.7} \times 10^{30}\,(d/2 {\rm \,\, kpc})^2$ erg s$^{-1}$ (1--10 keV). This is the lowest X-ray luminosity yet observed for a quiescent black hole X-ray binary, corresponding to an Eddington ratio $L_X/L_{\rm Edd} \sim 10^{-9}$. In 15 hours of observations with the Karl G. Jansky Very Large Array, no radio continuum emission is detected to a $3\sigma$ limit of $< 2.8\ \mu$Jy at 6 GHz. Including GS~2000+25, four quiescent stellar-mass black holes with $L_X < 10^{32}$ erg s$^{-1}$ have deep simultaneous radio and X-ray observations and known distances. These sources all have radio to X-ray luminosity ratios generally consistent with, but slightly lower than, the low state radio/X-ray correlation for stellar-mass black holes with $L_X > 10^{32}$ erg s$^{-1}$. Observations of these sources tax the limits of our current X-ray and radio facilities, and new routes to black hole discovery are needed to study the lowest-luminosity black holes. [Preview Abstract] |
Sunday, January 24, 2021 1:00PM - 1:10PM |
U12.00007: Impact of Orbital Dynamics on Dwarf Galaxy Quenching Near Massive Hosts Raven Cochrane, Charlotte Christensen, Gaen McCan, Coleman Thompson Dwarf galaxies provide a useful environment to study the forces driving galaxy evolution and quenching at small scale. Using numerical cosmological simulations of dwarf galaxy evolution, we examine the impact of orbital dynamics on the quenching of dwarf halos, particularly the significance of a halo's first infall into R$_{\mathrm{vir}}$ of the host. We analyzed very high resolution $\Lambda $CDM cosmological simulations centered on four Milky Way-mass hosts and their 29 satellites computed using the tree$+$SPH code CHANGA. We examined the distribution of the ratios of sSFR at infall to the average sSFR over the previous 1.05 Gyr, trends of sSFR and P$_{\mathrm{ram}}$ over time and distance, and dwarf halo orbital histories. We find that a dwarf halo's first infall into the host does not correspond with its peak SFR although there is often moderate enhancement. We find that P$_{\mathrm{ram}}$ is not distance-dependent until 6 Gyr into the simulation and that sSFR depends on time rather than distance. We find no evidence that increasing P$_{\mathrm{ram}}$ while approaching R$_{\mathrm{vir}}$ of the host contributes to the moderate sSFR enhancements at infall for most halos in the simulations. Our work implies that moderate SFR enhancements at infall before quenching are common although the mechanism responsible is unclear and requires more research. [Preview Abstract] |
Sunday, January 24, 2021 1:10PM - 1:20PM |
U12.00008: Probing the Statistical Relationship Between Binary Black Hole Mergers and Active Galactic Nuclei Hosts Amanda Beck, Yasmeen Asali, Eve Cully, Zsuzsa Marka Since 2015, LIGO/Virgo has detected many Binary Black Hole merger Gravitational Wave signals. Identifying the origins of these is key to discover more about these mergers. Rare host galaxies, like AGN, present a favorable environment for these events due to the possible dynamical interactions in their accretion disks. In this project we will probe the statistical relationship between BBH mergers and AGN hosts by analyzing the overlap in localization, as outlined in Bartos et. al. 2017. To do that, we developed a python-based framework that can get the volume overlap between AGN catalogs and LIGO/Virgo 90% probability density volume of BBH mergers. It can be used to establish the fraction of BBH GW detections that come from AGN and to inform real-time EM follow-up. [Preview Abstract] |
Sunday, January 24, 2021 1:20PM - 1:30PM |
U12.00009: Evidence for Triggered Star Formation by Collision of Molecular Filaments Natalie Kovacevic, Esteban D. Araya, Olga S. Bayandina, Irina E. Val’tts, Nadezhda N Shakhvorostova, Stan Kurtz, Peter Hofner As part of a study of low-frequency CH transitions as tracers of outflows in high-mass star forming regions, we conducted observations of the star forming regions G35.79-0.17 and G35.83-0.20 with the 305 m Arecibo Radio Telescope. We detected two 3.3 GHz CH spectral lines toward each source. The spectral lines are found at approximately the same LSR velocities, i.e., 28 and 60 km/s, which correspond to the systemic velocities of G35.83-0.20 and G35.79-0.17, respectively. The angular separation between both sources is 2.8 arcminutes. A Spitzer-IRAC image of the region shows a large scale (\textgreater 4 arcmin) infrared dark cloud (IRDC) filament, where both pointing positions are located. Given that the separation between both star forming regions is greater than the telescope beam, our data suggest that the two CH spectral lines are tracing the extended IRDC. We discuss the possibility that the two velocity components are tracing the interaction between two molecular clouds that triggers the star formation activity detected in the filament. As a broader-impact product of this work, we also present a Jupyter Notebook instructional activity that uses the data reported in this work to illustrate the basics of single-dish data reduction. [Preview Abstract] |
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