The extreme, red afterglow of GRB 060923A: Distance or dust?
Abstract
Gamma-ray bursts are powerful probes of the early universe, but locating and identifying very distant GRBs remains challenging. We report here the discovery of the K-band afterglow of Swift GRB 060923A, imaged within the first hour post-burst, and the faintest so far found. It was not detected in any bluer bands to deep limits, making it a candidate very high redshift burst (z>11). However, our later-time optical imaging and spectroscopy reveal a faint galaxy coincident with the GRB position which, if it is the host, implies a more moderate redshift (most likely z<2.8) and therefore that dust is the likely cause of the very red afterglow colour. This being the case, it is one of the few instances so far found of a GRB afterglow with high dust extinction.
Cite
@article{arxiv.0803.4100,
title = {The extreme, red afterglow of GRB 060923A: Distance or dust?},
author = {N. R. Tanvir and A. J. Levan and E. Rol and R. L. C. Starling and J. Gorosabel and R. S. Priddey and D. Malesani and P. Jakobsson and P. T. O'Brien and A. O. Jaunsen and J. Hjorth and J. P. U. Fynbo and A. Melandri and A. Gomboc and B. Milvang-Jensen and A. S. Fruchter and M. Jarvis and C. A. C. Fernandes and T. Wold},
journal= {arXiv preprint arXiv:0803.4100},
year = {2009}
}
Comments
Submitted to MNRAS (revised in light of referee's comments)