Spectral and temporal analysis of the joint Swift/BAT- Fermi/GBM GRB sample.

ABSTRACT Using the gamma-ray bursts (GRBs) simultaneously detected by Swift/Burst Alert Telescope (BAT) and Fermi/Gamma-ray Burst Monitor (GBM), we performed a joint spectral and temporal analysis of the prompt emission data and confirmed the rough correlation between the BAT-band photon index ΓBAT and the peak spectral energy Epeak. With the redshift-known subsample, we derived the isotropic gamma-ray energy Eγ, iso and also confirmed the Eγ,iso − Epeak,rest relation, with a larger scatter than the Amati sample but consistent with GBM team analyses. We also compare the T90 values derived in the GBM band with those derived in the BAT band and find that for long GRBs the BAT T90 is usually longer than the GBM T90, while for short GRBs the trend reverses. This is consistent with the soft/hard nature of long/short GRBs and suggests the importance of an energy-dependent temporal analysis of GRBs. [ABSTRACT FROM AUTHOR]