The first Swift BAT gamma-ray burst catalog

Abstract

We present the first Swift Burst Alert Telescope (BAT) catalog of gamma-ray bursts (GRBs), which contains bursts detected by the BAT between 2004 December 19 and 2007 June 16. This catalog (hereafter the BAT1 catalog) contains burst trigger time, location, 90% error radius, duration, fluence, peak flux, and time-averaged spectral parameters for each of 237 GRBs, as measured by the BAT. The BAT-determined position reported here is within 1.75′ of the Swift X-Ray Telescope (XRT)-determined position for 90% of these GRBs. The BAT T <inf>90</inf> and T<inf>50</inf> durations peak at 80 and 20 s, respectively. From the fluence-fluence correlation, we conclude that about 60% of the observed peak energies, E<inf>peak</inf>^obs, of BAT GRBs could be less than 100 keV. We confirm that GRB fluence to hardness and GRB peak flux to hardness are correlated for BAT bursts in analogous ways to previous missions' results. The correlation between the photon index in a simple power-law model and E <inf>peak</inf>^obs is also confirmed. We also report the current status for the on-orbit BAT calibrations based on observations of the Crab Nebula. © 2008. The American Astronomical Society. All rights reserved.