The First Swift Ultra-Violet/Optical Telescope GRB Afterglow Catalog

TL;DR

This paper introduces the first comprehensive catalog of UVOT afterglow observations for 229 gamma-ray bursts, providing detailed positional, temporal, and photometric data to aid GRB research.

Contribution

It presents the first UVOT GRB afterglow catalog with detailed photometry, positions, and light curves for over 229 GRBs, covering data from 2005 to 2007, including analysis of temporal slopes and correlations.

Findings

Median UVOT v-band magnitude at 2000s is 18.02.

Most light curves fit a single power-law with median slope 0.96.

Strong correlation between UVOT flux at 2000s and prompt BAT fluence.

Abstract

We present the first Swift Ultra-Violet/Optical Telescope (UVOT) gamma-ray burst (GRB) afterglow catalog. The catalog contains data from over 64,000 independent UVOT image observations of 229 GRBs first detected by Swift, the High Energy Transient Explorer 2 (HETE2), the INTErnational Gamma-Ray Astrophysics Laboratory (INTEGRAL), and the Interplanetary Network (IPN). The catalog covers GRBs occurring during the period from 2005 Jan 17 to 2007 Jun 16 and includes ~86% of the bursts detected by the Swift Burst Alert Telescope (BAT). The catalog provides detailed burst positional, temporal, and photometric information extracted from each of the UVOT images. Positions for bursts detected at the 3-sigma-level are provided with a nominal accuracy, relative to the USNO-B1 catalog, of ~0.25 arcseconds. Photometry for each burst is given in three UV bands, three optical bands, and a 'white' or open filter. Upper limits for magnitudes are reported for sources detected below 3-sigma. General properties of the burst sample and light curves, including the filter-dependent temporal slopes, are also provided. The majority of the UVOT light curves, for bursts detected at the 3-sigma-level, can be fit by a single power-law, with a median temporal slope (alpha) of 0.96, beginning several hundred seconds after the burst trigger and ending at ~1x10^5 s. The median UVOT v-band (~5500 Angstroms) magnitude at 2000 s for a sample of "well" detected bursts is 18.02. The UVOT flux interpolated to 2000 s after the burst, shows relatively strong correlations with both the prompt Swift BAT fluence, and the Swift X-ray flux at 11 hours after the trigger.