PhD Thesis Defense
Friday, August 13, 2021 - 13:00
Event Speaker: 
Tyler Parsotan
Local Contact: 
Davide Lazzati

Gamma Ray Bursts (GRBs) are the most energetic explosions in the Universe, producing up to < 1053 ergs of energy in the first few seconds of their prompt phase which is dominated by high energy X-ray and γ-ray photons. The large luminosities released in these events make GRBs an ideal laboratory for exploring the interplay between matter and radiation under extreme conditions. While available GRB data has contributed to a general understanding of these events, there is still much more information hidden in the data which can shed light on: the microphysical processes that are relevant to radiation from jets, the properties of the GRB jet, and how the jet imprints its signature on the resulting radiation. The Monte Carlo Radiation Transfer code (MCRaT) studies the interplay between matter and radiation by conducting radiative transfer calculations using a realistic jet profile acquired from special relativistic hydrodynamic simulations (SRHD) of GRBs. MCRaT injects thermal photons into the jet and Compton scatters and propagates the photons through the outflow, taking their polarization into account. Using MCRaT we show that GRB SRHD simulations are able to reproduce common features of observed GRB spectra and the Yonetoku and Golenetskii relationships. Furthermore, we show that the expected polarization signatures are also in agreement with the polarimetric GRB observations. Due to the ability of MCRaT to conduct radiation transfer calculations using the background of a realistic jet profile, we are able to begin understanding the complex relationship between the progenitor material, the jet matter and the radiation signature.