Prompt Optical Detection of GRB 050401 with ROTSE-IIIa
Abstract
The ROTSE-IIIa telescope at Siding Spring Observatory, Australia, detected prompt optical emission from Swift GRB 050401. We present observations of the early optical afterglow, first detected by the ROTSE-IIIa telescope 33 s after the start of γ-ray emission, contemporaneous with the brightest peak of this emission. This GRB was neither exceptionally long nor bright. This is the first prompt optical detection of a GRB of typical duration and luminosity. We find that the early afterglow decay does not deviate significantly from the power-law decay observable at later times and is uncorrelated with the prompt γ-ray emission. We compare this detection with the other two GRBs with prompt observations, GRB 990123 and GRB 041219a. All three bursts exhibit quite different behavior at early times.
- Publication:
-
The Astrophysical Journal
- Pub Date:
- October 2005
- DOI:
- 10.1086/497370
- arXiv:
- arXiv:astro-ph/0508495
- Bibcode:
- 2005ApJ...631L.121R
- Keywords:
-
- Gamma Rays: Bursts;
- Astrophysics
- E-Print:
- 4 pages, 3 figures. Accepted for publication in ApJ Letters