Statistics On Gamma-ray Bursts Afterglow And Host Galaxies, And The Central Engine Model Of GRB 110918A

Vela satellite observed the first gamma-ray burst(GRB) in 1973,then we know GRB is a high-energy astrophysical physics phenomenon, and it is a phenomenon of gamma rays suddenly break out in a short interval. With the launch of GRB satellites and the establishment of more and more ground-based observatories, we can obtain more GRBs data and the quality of data is improved gradually. The launch of Swift and Fermi satellite have taken us into a new era of GRBs research, and we can get more GRBs afterglow and host galaxies data, which help us greatly in studying GRBs.The researches in my thesis focus on the data statistics of GRBs afterglow and host galaxies: Firstly, the first chapter is an overview of gamma-ray bursts. I introduce the history and global distribution of GRBs and summary the prompt radiation and afterglow observation of GRBs, as well as some important empirical relations and the distribution of host galaxies.Secondly, my thesis describes GRBs progenitors, center engine model and hot fireball model. I mainly describe three possible central engine model: magnetar model, NDAF model and BZ model, and summary the GRB fireball dynamics and standard fireball shock model. The first two chapters are my learning and understanding in GRBs basic knowledge, and they are foundation of completing my work during postgraduate.Thirdly, I introduce some of my work during postgraduate. The third chapter introduces the broad-band afterglow data fitting and central engine of GRB 110918 A. Considering the Wind and ISM medium of burst, we use the X-ray, optical and near-infrared afterglow data obtaining afterglow light curves and spectrums, as well as two groups of fitting parameters. Combining the limiting of its initial Lorentz factor with theoretical analysis, I consider the central engine of GRB 110918 A is BZ model. The fourth chapter is about the correlation studies between radio luminosity and X-ray luminosity of GRBs, and whether the relationship is similar to active galactic nuclei(AGN), sun flares and cold stars. We collect 47 GRBs radio and X-ray luminosity data, and find they are really similar. It indicates that different scales objects are likely have same origin. My first two works mainly involve GRBs afterglow data statistics and fitting, and my last work is about the statistics on GRBs host galaxies. We establish a “big statistics table” of GRBs and their host galaxies. I am responsible for collecting host galaxies shape, offset, metallicity, absolute luminosity, AB magnitude, hydrogen column density, extinction, star formation rate, age and mass. And I obtain eight histograms about host galaxies data. I introduce this work in fifth Chapter.Finally, I summarize the main content of my thesis, and prospect several problems to be solved in GRBs study.