Prof. Bing Zhang received a near $400,000 research grant from NASA's Astrophysics Theory Program. The grant is to support his research group in developing novel theoretical models of relativistic astrophysical jets in the magnetically dominated regime. The models will use a relativistic magnetohydrodynamic (MHD) code and conduct global and local simulations of colliding magnetically dominated shells. They also will investigate the detailed physical processes of collision-triggered magnetic reconnection and dissipation, particle acceleration and radiation, as well as the light curves, spectra, and polarization properties of the emission. The results from the proposal will be applied to understand the physical mechanisms of gamma-ray bursts and other relativistic jets in the universe.
Thursday, May 7, 2015
Monday, May 4, 2015
May 14, 2015 1:00PM BPB-217. PhD. Defense: Wei Deng, Study the Mechanism of the Prompt Emission of Gamma-Ray Bursts.
PhD Defense
The prompt emission of Gamma-Ray Bursts (GRBs) has been detected over 40 years, but the mechanism of the prompt emission is still a mystery. The problem can be summarized as several debatable questions: What is the energy composition of the jets/outflows? What is the energy dissipation mechanism? How are the particles accelerated during the energy dissipation process? What is the radiation mechanism to produce the observed prompt emission? In order to solve these problems, several theoretical models have been proposed, including the classical "internal shock (IS)" model, the "dissipative photosphere" model, and the "Internal-Collision-induced MAgnetic Reconnection and Turbulence (ICMART)" model. This dissertation includes two parts. The first part is related to the photosphere model of prompt emission. The second part presents a global special relativistic MHD simulations based on the ICAMRT scenario.