Bulletin of the American Physical Society
Four Corners Section 2022 Meeting
Volume 67, Number 14
Friday–Saturday, October 14–15, 2022; Albuquerque, New Mexico
Session E04: Astrophysics II |
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Chair: Greg Taylor, UNM Room: UNM PAIS 1160 |
Friday, October 14, 2022 2:30PM - 2:54PM |
E04.00001: SPITZER to JWST : Mid-infrared spectra of Brown Dwarfs is back! Invited Speaker: Denise Stephens From 2003 to 2009 the Spitzer Space Telescope obtained the first spectra of brown dwarfs from 5 to 15 microns. This led to the identification of a number of critical molecular features including ammonia in the T dwarfs and silicate grains in the L dwarfs. When Spitzer's cryogen was depleted, our ability to probe the atmospheres of the coolest free-floating objects in the mid-infrared was lost. With the arrival of JWST, we are once again obtaining data and probing the chemistry of brown dwarfs and planet-mass objects in the mid-infrared. But this time we are observing objects that are much colder and much smaller in mass, and we have a new suite of tools and models to analyze the data. In this talk, I will highlight what we learned from Spitzer and how that prepared us for JWST. I will share the new tools we are using to model the atmospheres of these objects. Finally, I will highlight some of the early JWST results and outline what is coming in the future. |
Friday, October 14, 2022 2:54PM - 3:06PM |
E04.00002: Evaluating the E-Field Parallel Imaging Correlator (EPIC) with the Long Wavelength Array Craig A Taylor, Greg B Taylor, Jayce Dowell Wide-field imaging using the E-Field Parallel Imaging Correlator (EPIC) architecture for interferometric arrays has been shown to be an effective method for high-cadence, all-sky observations (Thyagarajan et al. 2017). This parameter space in high-resolution imaging arrays was previously inaccessible with traditional correlation algorithms due to the high computation load associated with gridding or FFT-based methods (Kent et al. 2019). The EPIC formalism was demonstrated using the Long Wavelength Array (LWA) in Kent (2019) and motivates further testing and comparison of this electric field-based direct imaging method with traditional correlated imaging. We present an observation of Crab Pulsar using standard FX-correlated observations with the LWA Sevilleta Station (LWA-SV) and its commensal EPIC imaging mode. Comparing these results provides essential insight on how the two observing modes function, and how we can exploit the strengths of both instruments in future LWA research of Pulsars, Fast Radio Bursts, and other fast time-domain transient phenomena. |
Friday, October 14, 2022 3:06PM - 3:18PM |
E04.00003: Scale-Free Dynamics of Monopole-Quadrupole Binaries Applied to the Morphogenesis of Bi-lobed KBOs Leon N Tong, Oleg Korobkin, Irina Sagert A significant fraction of Kuiper Belt Objects (KBOs) are observed to have strongly asymmetric, particularly bi-lobed, shapes. Arrokoth, recently imaged by the New Horizons space probe, is one example of a KBO with such shape. Such morphologies suggest an origin from a gentle collision between two smaller bodies that were in a binary. A recent study by Grishin et al. (Nature, 2020) suggested that chaotic Kozai-Lidov (KL) oscillations might be responsible for causing the orbiting binary to collide and produce a highly irregular, bi-lobed object. Another possibility, which can also be extended to systems with a broad range of scales, is an orbital eccentricity evolution due to spin-orbit coupling that may also bring two bodies to a merger. Here we present a new code for evolving perturbed binaries in which the shape of the secondary is taken into account by approximating it as a gravitating quadrupole. We use quaternion algebra for representing orientation of the secondary and derive equations of motion based on MacCullagh's formula. We present several tests of the code and discuss possible pathways for the morphogenesis of bi-lobed objects from such systems. Indeed, in a system with strong spin-orbit coupling, one might expect eccentricity oscillations similar to those produced by KL mechanism when the spin of the secondary is not aligned with orbital angular momentum. It is also important to take into account spin-orbit coupling at the periapsis of the KL cycle, as it might strongly alter the outcome of KL-triggered encounters. |
Friday, October 14, 2022 3:18PM - 3:30PM |
E04.00004: Status of the Extreme Universe Space Observatory on a Super Pressure Balloon 2 Hannah L Wistrand, Lawrence R Wiencke The Extreme Universe Space Observatory on a Super Pressure Balloon 2 (EUSO-SPB2) mission will make new measurements from suborbital space as a precursor for future space missions that aim to identify the sources ultra-high energy cosmic rays and very high energy neutrinos. The EUSO-SPB2 payload features two 1m diameter aperture telescopes. The Fluorescence Telescope (FT), which will point down, will record fluorescence light from cosmic ray EASs with energies above 1EeV in its field of view of 36 by 12 degrees. The Cherenkov Telescope (CT) features a silicon photomultiplier camera system with a field of view of 12 by 6 degrees that will point near the Earth’s limb. Below the limb, the CT will follow up on alerts of binary black hole merger, ??binary neutron star merger, gamma-ray burst, and tidal disruption event candidates by searching for Cherenkov emission from PeV-scale EASs induced by tau neutrinos. When tilted above the limb, the CT will measure Chernkov light from direct cosmic rays. EUSO-SPB2 is on track for launch on a NASA super pressure balloon payload in April of 2023 from Wanaka NZ. I will report on the status of the project, the desert field tests of the telescopes, and my contributions to the project. |
Friday, October 14, 2022 3:30PM - 3:42PM |
E04.00005: Jets and Outflows from High-Mass Protostars from a Multi-Scale and Multi-Wavelength Point of View Tatiana M Rodríguez, Peter Hofner, Esteban D Araya Even though high-mass stars (M* > 8 Msun) are of great importance in Astrophysics, many questions remain unanswered regarding their formation. One proposed model is a scaled-up version of the core accretion process, similar to the formation of low-mass stars. In this scenario, bipolar jets and outflows play a key, yet poorly understood role in shedding excess angular momentum and regulating the star formation process. A large variety of physical processes occur during the launching of flows, including complex interactions with the surrounding medium. In the last two decades, a variety of shock tracers ranging from radio wavelengths to the high energy regime have been observed from outflows on scales from a few au to several pc. Thus, observations with different instruments and over a wide frequency range are necessary to fully grasp the nature and role of jets and outflows during high-mass star formation. In this talk, I will present results of my research on outflows, jets, and masers using radio interferometric data, and also review recent discoveries in the IR and high energy regime. |
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