The Energy Spectral Characteristics And Energy Mechanisms Of γ-ray Bursts

Gamma-ray bursts are astrophysical phenomena with high energy and short scales, which are first discovered in 1970s. There are three stages in the history of the researches: the studies of spectral structures at early stage( 1973 ~ 1991), the debates of the source distances from us( 1991 ~ 1997) and the studies of the afterglows of Y-ray bursts(1997~ ).In this paper, we analyze the observable characteristics of Y -ray bursts in detail, including time scales, energy spectra and space distribution. It is showed that the time scales range from 0.01s to 1000s, the energy spectra range from IKeV to lOOMeV and Y -ray bursts have an isotropic distribution in galactic sphere. Some typical bursts are discussed and regarded as two types of sources: classical burst and soft repeater.The fireball model is universally accepted as the standard model in explaining Y -ray bursts. Here we adequately review the model and study a few mechanisms which lead to the production of the fireball. It is pointed out that the models involving strange stars have the advantage for explaining the energy source of bursts, which can overcome the baryon pollution of the fireball.