Bulletin of the American Physical Society
2021 Joint Spring Meeting of the Texas Sections of APS, AAPT and Zone 13 of the SPS
Volume 66, Number 2
Thursday–Sunday, April 8–11, 2021; Virtual
Session C21: APS: Astrophysics and Space Science-IV |
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Saturday, April 10, 2021 3:00PM - 3:12PM |
C21.00001: Heightened Carbon Abundances in Binary CEMP-no Stars Elyse Harman, Terese Hansen Abundance analysis of the oldest and most metal-poor low mass stars in our Universe has revealed a large fraction of these to be enhanced in carbon (CEMP-no stars). The distribution of carbon abundances for CEMP-no stars has been found to be bimodal splitting into a high and low carbon group. The abundance patterns are generally believed to reflect the nucleosynthesis of the first supernovae exploding in the Universe; however, we show that stars belonging to the high-carbon group are more likely to be binaries. This reveals two potential paths of evolution for CEMP-no stars based on binary status, as binary stars may have accumulated higher carbon abundances by mass transfer within the binary system. We also are working to expand the sample of CEMP-no stars for which we have abundance and radial velocity data to further this study. [Preview Abstract] |
Saturday, April 10, 2021 3:12PM - 3:24PM |
C21.00002: The future of massively multiplexed spectroscopy: the Maunakea Spectroscopic Explorer Jennifer Marshall The Maunakea Spectroscopic Explorer (MSE) is a planned next generation massively multiplexed spectroscopic facility that is completely dedicated to optical and near-Infrared spectroscopy of samples of thousands to millions of astrophysical objects at resolutions from R~3,000 to R~40,000. With science goals spanning all of astronomy, from detailed chemical abundance studies of nearby stars to investigating the cosmology of the early Universe, MSE will provide key next-generation science capabilities that will revolutionize the field. In this talk I will review the current status of the project and provide an overview of MSE's wide range of scientific capabilities. [Preview Abstract] |
Saturday, April 10, 2021 3:24PM - 3:36PM |
C21.00003: A Probabilistic Approach to Infer the Unknown Redshifts of Long-duration Gamma-Ray Bursts Observed by BATSE Joshua Osborne, Amir Shahmoradi, Robert Nemiroff Here we present a purely probabilistic approach to inferring the redshifts for 1366 Long-duration Gamma-Ray Bursts (LGRBs) as detected by the Burst and Transient Source Experiment (BATSE). This is done through a careful modeling of the underlying redshift distribution and four intrinsic prompt gamma-ray emission properties: the spectral peak energy (Epz), the isotropic 1024ms peak luminosity (Liso), the total isotropic emission (Eiso), as well as the intrinsic duration (T90z). Additionally, we also take into account both the sample incompleteness of our dataset as well as the BATSE detection mechanism. There are two fundamental assumptions to our approach: 1. LGRBs trace the Cosmic Star Formation Rate and 2. the joint 4-dimensional distribution of the prompt gamma-ray emission properties can be modeled by a multivariate log-normal distribution. We then explore the posterior Probability Density Functions (PDFs) using the Parallel Delayed-Rejection Adaptive Metropolis-Hastings Markov Chain Monte Carlo (ParaDRAM) algorithm in order to find the optimal parameters for our intrinsic properties distributions and using this calibrated model we are then able to constrain the PDFs of the redshift distribution. Lastly, we compare our results to previous redshift estimates of other works. [Preview Abstract] |
Saturday, April 10, 2021 3:36PM - 3:48PM |
C21.00004: Extension of local spiral structure based on massive OB-stars to Gaia EDR3 William Chisholm, Louis Strigari Gaia Early Data Release 3 provides precise parallaxes for a large sample of massive OB-stars. This precise astrometry allows for an investigation of local Milky Way spiral structure. We use a compiled list of OB-stars in the local galactic arms containing astrometric solutions derived from Gaia DR2, and we crossmatch given Gaia DR2 sources to find Gaia EDR3 counterparts. Additionally, a crossmatch with Hipparcos was performed. We have compiled a list of ∼250 O-sources and ∼4,000 B-stars with positions in the galactic Cartesian frame. The improvements on the accuracies of these sources substantiate previous analysis of local spiral structure. [Preview Abstract] |
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