Isotropic Luminosity-Lorentz Factor Correlation Of Gamma-Ray Bursts And Its Physical Implication

Gamma-Ray Burst (GRB) is a phenomenon of short and intense pulses of gamma rays occurred in space. GRBs were unexpected discovery in the late1960s by the Vela satellite, which caused widespread concern of astronomers and astrophysicists. In the last two decades, some space missions---CGRO/BATSE, BeppoSAX, HETE II (High-Energy Transient Explorer), together with the ground-based optical, infrared, and radio observatories are changing our understanding of GRBs. GRBs are cosmological events and accompanied with long-lasting afterglows. The Swift satellite dedicated to study the GRBs and the Fermi satellite covering large energy range, successfully launched in2004and2008respectively, have taken us into a new era of GRB research.The main direction of this thesis is the correlation between Lorentz factor and mean isotropic luminosity/energy of GRBs, and interpretation with neutrino dominated accretion flow (NDAF) model of central engine of GRBs. This work involves the central engine of GRB and data statistical analysis of observed quantities of GRBs. The thesis is structured as follows:Chapter I is the review of GRBs, including the observations of prompt radiation and afterglow of GRBs, radiation mechanisms, central engine of GRBs and some important relations of GRBs. In Chapter II, we give the statistical fitting and theoretical analysis with NDAF model between initial Lorentz factor and the isotropic equivalent luminosity or isotropic equivalent energy of GRBs. The initial Lorentz factor is a very important parameter to understand the physics of GRBs, especially for understanding the physical origin of the prompt GRB emission phase. We apply several commonly used methods to constrain the initial Lorentz factor of GRBs in Chapter II, and give the details of NDAF model and the Lorentz factor statistics of51GRBs with known redshifts. Chapter III is about the correlation studies between radio luminosity and X-ray luminosity of GRBs, and whether the relationship can be extended to the sun, cool stars and active galactic nuclei. Finally, we summarize the important findings of GRBs in the past several years and the problems we hope to solve in future.This thesis provides detailed calculations of the initial Lorentz factor of gamma-ray burst, and gives the relationship between initial Lorentz factor and isotropic equivalent luminosity of GRBs, meanwhile it proposes an interpretation to the statistical correlation within the framework of a blackhole-NDAF disk GRB central engine model.