Astronomy Tea Talk

Speaker 1: Rahul Jayaraman

Title: Observing Gamma-Ray Bursts with the Transiting Exoplanet Survey Satellite

Abstract:

The early-time behavior of gamma-ray bursts at optical wavelengths remains poorly studied, due to the serendipity (and/or rapid slewing) required to observe these events as part of ground-based surveys. In particular, the prompt optical emission from GRBs has been found to disagree with the extrapolation of phenomenological models for the high-energy emission. In my talk, I will discuss my work using the Transiting Exoplanet Survey Satellite (TESS) to characterize prompt optical emission from GRBs. TESS is uniquely suited to this task due to its continuous stare times of 27 days for its 2300 deg^2 field of view, as well as its 200 second imaging cadence. I will discuss my analysis of optical light curves of well-localized GRBs in TESS, as well as my investigation into how these bursts' high energy spectra relate to the observed prompt optical flux. Through TESS observations, I have been able to establish the first-ever limits on prompt optical emission from short GRBs. I will also briefly discuss my development of a transient detection pipeline to search large localizations, such as those from the Gamma-ray Burst Monitor on board the Fermi Telescope. Finally, I will discuss the prospects of using this pipeline to search for orphan afterglows in the TESS data, and the expectations for TESS as it moves into its Third Extended Mission.

Speaker 2: Jesse Han

Title: Mapping the Dynamics, Dark matter, and Dense clouds of the Galaxy

Abstract:

I will present new discoveries about the phase space distribution of stars in the Galactic halo, which in turn can constrain the underlying dark matter distribution. Based on these new insights, I offer a solution to the long-standing problem on the warp (and flare) of the Galactic disk. Furthermore, I show that the same dataset used to study the stellar halo can also be used to constrain the distribution of cold, dense gas in the circum-galactic and interstellar medium. To conclude, I will introduce a transformative all-sky survey with NASA's Roman Space Telescope, poised to revolutionize our understanding of the Galactic halo and potentially uncover hidden dark matter substructures within our Galaxy.