Duration distributions for gamma-ray bursts registered in various experiments since VENERA11/KONUS up to Fermi/GBM.

摘要

Gamma-ray bursts duration distributions properties for events registered by experiments CGRO/BATSE, VENERAI 1/KONUS, VENERA 12/KONUS, Swift/BAT, GRANAT/PHEBUS, Suzaku/WAM, RHESSI and Fermi/GBM are considered. GRBs observed since 1967 and now several thousands of events were listed in more than 30 catalogues. Gamma-ray bursts duration distribution was the first analysed using data of BATSE instrument onboard the CGRO. The GRBs duration distribution analysis had shown the existence of two bursts classes: long and short separated by t_(90)= 2 s. But results of similar distributions for bursts observed by other detectors have shown shifting of boundary between short and long events from value of 2 s. For example, Swift/BAT GRBs subset analysis gives the value of ~1 s for this separator point. Moreover, t_(90) has dependence from instrument registered this burst - it is function of detector sensitivity threshold and operation energy band. For instance, the duration of GRB060418 burst t_(90) is -52 s according to Swift/BAT data and only 36 s according to RHESSI data. Therefore, the type of GGB (whether it short or long) should be defined only taking into account distinctive features of instrument detected this event. Also attributes of third intermediate GRBs subgroup appearance in events subsets for various detectors are discussed. Firstly this subgroup was found some years ago in BATSE GRB duration and duration-hardness distributions.