Optical emission from GRB 050709: a short/hard GRB in a star forming galaxy
Abstract
We present optical observations of the short/hard gamma-ray burst GRB 050709, the first such event with an identified optical counterpart. The object is coincident with a weak X-ray source and is located inside a galaxy at redshift z = 0.1606 +- 0.0002. Multiband photometry allowed us to study the broad-band spectral energy distribution. Late-time monitoring places strong limits on any supernova simultaneous with the GRB. The host galaxy is not of early type. Spectra show that the dominant stellar population is relatively young (~ 1 Gyr), and that ongoing star formation is present at a level of 2-3 (L/L*) Msun/yr. This is at least 2 orders of magnitude larger than that observed in the elliptical hosts of the short GRB 050509B and GRB 050724. This shows that at least some short GRBs originate in a young population. Short/hard GRB models based on the merger of a binary degenerate system are compatible with the host galaxy characteristics, although there is still the possibility of a connection between young stars and at least a fraction of such events.
Cite
@article{arxiv.astro-ph/0509144,
title = {Optical emission from GRB 050709: a short/hard GRB in a star forming galaxy},
author = {S. Covino and D. Malesani and G. L. Israel and P. D'Avanzo and L. A. Antonelli and G. Chincarini and D. Fugazza and M. L. Conciatore and M. Della Valle and F. Fiore and D. Guetta and K. Hurley and D. Lazzati and L. Stella and G. Tagliaferri and M. Vietri and S. Campana and D. N. Burrows and V. D'Elia and P. Filliatre and N. Gehrels and P. Goldoni and A. Melandri and S. Mereghetti and I. F. Mirabel and A. Moretti and J. A. Nousek and P. T. O'Brien and L. J. Pellizza and R. Perna and S. Piranomonte and P. Romano and F. M. Zerbi},
journal= {arXiv preprint arXiv:astro-ph/0509144},
year = {2010}
}
Comments
4 pages, 4 figures, accepted for publication in A&A Letters