Spectral Lag Effect Between High And Low Photons And Light Curve Pulse In GRBs

Gamma-ray bursts(GRBs) is a kind of cosmological phenomena in which the gamma-ray increase rapidly in short time scale. It's extra high energy, prompt burst, extra short time scale and complex construction of time and spectrum are very important in research of GRBs. In this thesis, the observational properties and main theoretical models on GRBs and their afterglow are reviewed, and present in detail the results of our tow research work on spectral lag between high and low photons and light curve of pulse in GRBs.We present a detailed analysis on the spectral lags of the short GRBs and compare them with that of the long GRBs. Our sample includes 308 short GRBs and 1008 long GRBs. We calculate the cross-correlation function (CCF) for the light curves in 25-55 and 110-300 keV bands and derive the spectral lag by fitting the CCF with the Gaussian model. Our results are as follows. (1) The spectral lag distribution of the short GRBs is significantly different from that of the long GRBs. Excluding the statistical fluctuation effect, a proportion of about 17 percent of the short GRBs has a negative spectral lag, i.e. the hard photons are being lag behind the soft photons. We do not find any peculiar features from their light curves to distinguish these bursts from those with a positive spectral lag. This should be a great challenge to the current GRB models. We note that this...