报告题目：Modeling the central engine of GRBs and their related phenomena

报告时间：2022年05月13日，星期五，北京时间17:00-18:30

ZOOM LINK:

https://us05web.zoom.us/j/81809781439?pwd=RXY3M0FVQ0Qwb0xCQjZIVGxiWTVoUT09

Meeting ID: 818 0978 1439

Passcode: Astro

报告专家：Prof. Shahram Abbassi,Ferdowsi University of Mashhad

报告摘要：

Gamma-ray bursts (GRBs) are the most luminous explosions in the Universe, and their origin and mechanism are the focus of intense research and debate. Black hole hyperaccretion model is one of the plausible candidates for the central engine of gamma-ray bursts and their activity is supposed to result in the complicated explosion phenomena including gamma-ray bursts, gravitational waves, and their electromagnetic counterparts. In the inner regions of such disks, photons are totally trapped due to high density and temperature. Getting cool through neutrinos and antineutrinos efficiently, these accretion disks are also called Neutrino Dominated Accretion Flows (NDAFs). Moreover, the high magnetic field (∼ 10^15−16G) and large density (∼ 10^10g cm−3) can be considered as the two important physical features of these disks, and as a result, self-gravity and gravitational instability might be of a crucial role in these dense hyperaccretion flows. As well, the magnetic field is proposed to be of considerable importance via both large and small scale impacts. After providing an introduction to the GRB’s and the candidates of their central engines, we focus on these two factors (self-gravity and magnetic field) to probe their potential effects on the hyperaccretion disk’s structure, in addition to their subsequent impacts on the GRB’s spectral features. In other words, we apply these two features to provide an explanation for the prompt Gamma-ray emission with its highly variable structure in the early time, and the electromagnetic afterglow emission associated with the late time activity of the GRB’s central engine.

报告专家简介:

Professor Shahram Abbassi obtained his Ph.D. in Astrophysics from Ferdowsi University of Mashhad, Iran in 2005. He was non-resident researcher at IPM institute for research in fundamental science, from 2008-2017. He was also regular Associate of International center for theoretical physics (ICTP), Trieste Italy, 2015-2020. He was awarded by Iran Science Elite Federation (one of the 100 scientists) 2015, 2016, 2017. Shahram Abbassi’s research interests include Formation of Stars, Dynamics and evolution of Accretion discs, Stellar Oscillations, Neutrino-dominated accretion flows and Gamma-ray bursts, and Astrophysics and Astro-seismology of compact objects.