The First Swift BAT Gamma-Ray Burst Catalog

TL;DR

This paper presents the first Swift BAT gamma-ray burst catalog, detailing 237 GRBs with their properties, and confirms correlations between fluence, peak flux, and spectral hardness, providing valuable data for GRB studies.

Contribution

It introduces the first comprehensive Swift BAT GRB catalog, including detailed measurements and analysis of burst properties and spectral correlations.

Findings

BAT GRB durations peak at 80 and 20 seconds.

Approximately 60% of GRBs have Epeak less than 100 keV.

Confirmed correlations between fluence, peak flux, and spectral hardness.

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 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_90 and T_50 durations peak at 80 and 20 seconds, respectively. From the fluence-fluence correlation, we conclude that about 60% of the observed peak energies, Epeak, 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 Epeak is also confirmed. We also report the current status for the on-orbit BAT calibrations based on observations of the Crab Nebula.