The Neil Gehrels Swift Observatory

The Swift/BAT Second GRB Catalog

Sakamoto et al. (2013) published this catalog of GRBs detected with the BAT (ADS).


Wepresent the second Swift Burst Alert Telescope (BAT) catalog of gamma-ray bursts (GRBs), which contains 476 bursts detected by the BAT between 2004 December 19 and 2009 December 21. This catalog (hereafter the BAT2 catalog) presents burst trigger time, location, 90% error radius, duration, fluence, peak flux, time-averaged spectral parameters, and time-resolved spectral parameters measured by the BAT. In the correlation study of various observed parameters extracted from the BAT prompt emission data, we distinguish among long-duration GRBs (L-GRBs), short-duration GRBs (S-GRBs), and short-duration GRBs with extended emission (S-GRBs with E.E.) to investigate differences in the prompt emission properties. The fraction of L-GRBs, S-GRBs, and S-GRBs with E.E. in the catalog are 89%, 8%, and 2%, respectively. We compare the BAT prompt emission properties with the BATSE, BeppoSAX, and HETE-2 GRB samples. We also correlate the observed prompt emission properties with the redshifts for the GRBs with known redshift. The BAT T90 and T50 durations peak at 70 s and 30 s, respectively. We confirm that the spectra of the BAT S-GRBs are generally harder than those of the L-GRBs. The time-averaged spectra of the BAT S-GRBs with E.E. are similar to those of the L-GRBs. Whereas, the spectra of the initial short spikes of the S-GRBs with E.E. are similar to those of the S-GRBs. We show that the BAT GRB samples are significantly softer than the BATSE bright GRBs and that the time-averaged Eobspeak of the BAT GRBs peaks at 80 keV, which is significantly lower energy than those of the BATSE sample, which peak at 320 keV. The time-averaged spectral properties of the BAT GRB sample are similar to those of the HETE-2 GRB samples. By time-resolved spectral analysis, we find that only 10% of the BAT observed photon indices are outside the allowed region of the synchrotron shock model. We see no obvious observed trend in the BAT T90 and the observed spectra with redshifts. The T90 and T50 distributions measured at the 140‑220 keV band in the GRB rest frame from the BAT known redshift GRBs peak at 19 s and 8 s, respectively. We also provide an update on the status of the on-orbit BAT calibrations.


T. Sakamoto1,2,3, S. D. Barthelmy3, W. H. Baumgartner1.2.3, J. R. Cummings1,2,3, E. E. Fenimore4, N. Gehrels3, H. A. Krimm1,3,5, C. B. Markwardt3, D. M. Palmer4, A. M. Parsons3, G. Sato6, M. Stamatikos7, J. Tueller3, T. N. Ukwatta8, and B. Zhang9

1Center for Research and Exploration in Space Science and Technology (CRESST), NASA Goddard Space Flight Center, Greenbelt, MD 20771, USA
2Joint Center for Astrophysics, University of Maryland, Baltimore County, 1000 Hilltop Circle, Baltimore, MD 21250, USA
3NASA Goddard Space Flight Center, Greenbelt, MD 20771, USA
4Los Alamos National Laboratory, P.O. Box 1663, Los Alamos, NM 87545, USA
5Universities Space Research Association, 10211 Wincopin Circle, Suite 500, Columbia, MD 21044-3432, USA
6Institute of Space and Astronautical Science, JAXA, Kanagawa 229-8510, Japan
7Center for Cosmology and Astro-Particle Physics, Department of Physics, The Ohio State University, 191 West Woodruff Avenue, Columbus, OH 43210, USA
8Department of Physics and Astronomy, Michigan State University, 3245 BPS Building, East Lansing, MI 48824, USA
9Department of Physics and Astronomy, University of Nevada, Las Vegas, NV 89154, USA

Data Access

The catalog itself is available from this IOPSCIENCE website.