Astronomy and Astrophysics – Astrophysics
Scientific paper
2005-05-12
Astron.Astrophys. 439 (2005) 527-532
Astronomy and Astrophysics
Astrophysics
Accepted for publication in A&A, 6 pages, 2 figures
Scientific paper
10.1051/0004-6361:20052948
We present a photometric study of the optical counterpart of the long-duration Gamma Ray Burst (GRB) 030725, which triggered the HETE FREGATE and WXM instruments on July 25th, 2003, and lasted more than 160s. An optical counterpart was identified at the Bronberg Observatory in South Africa about 7 hours after the burst occurred. The optical afterglow (OA) was observed between 4 and 15 days after the burst with the 1.54m Danish telescope at La Silla in the V, Rc, and Ic bands. We fit a broken power law to the data and determine a break time in the light curve between 16 hours and 4.7 days after the first detection of the burst. The decay slope is alpha1 = -0.59 +0.59/-0.44 before and alpha2 = -1.43 +/- 0.06 after the break. A bump may be present in the light curve, only significant at the 2-sigma level, 13.9 days after the main burst. The spectral slope of the OA, measured 12 days after the burst, is -2.9 +/- 0.6 , i.e. it falls in the extreme red end of the distribution of previous OA spectral slopes. Observations of the field 8 months after the burst with the EMMI instrument on the NTT telescope (La Silla) resulted in an upper limit of Rc=24.7 mag for the host galaxy of GRB 030725. The OA of GRB 030725 was discovered at a private, non-professional observatory and we point out that with the current suite of gamma ray satellites, an effort to organize future contributions of amateur observers may provide substantial help in GRB light curve follow up efforts.
Fynbo Johan P. U.
Gorosabel Javier
Hjorth Jens
Jensen Brian L.
Jørgensen S. F.
No associations
LandOfFree
The red optical afterglow of GRB 030725 does not yet have a rating. At this time, there are no reviews or comments for this scientific paper.
If you have personal experience with The red optical afterglow of GRB 030725, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and The red optical afterglow of GRB 030725 will most certainly appreciate the feedback.
Profile ID: LFWR-SCP-O-163919