A short g-ray burst apparently associated with an elliptical galaxy at redshift z = 0.225

• Published in: Nature (London) 2005-10, Vol.437 (7060), p.851-854
• Main Authors: Gehrels, N, Sarazin, C L, O'Brien, P T, Zhang, B, Barbier, L, Barthelmy, S D, Blustin, A, Burrows, D N, Cannizzo, J, Cummings, J R, Goad, M, Holland, S T, Hurkett, C P, Kennea, J A, Levan, A, Markwardt, C B, Mason, K O, Meszaros, P, Page, M
• Format: Article
• Language: English
• ISSN: 0028-0836
• DOI: 10.1038/nature04142

Gamma-ray bursts (GRBs) come in two classes: long ( > 2 s), soft-spectrum bursts and short, hard events. Most progress has been made on understanding the long GRBs, which are typically observed at high redshift (z 1) and found in subluminous star-forming host galaxies. They are likely to be produced in core- collapse explosions of massive stars. In contrast, no short GRB had been accurately ( < 10") and rapidly (minutes) located. Here we report the detection of the X-ray afterglow from: and the localization of: the short burst GRB 050509B. Its position on the sky is near a luminous, non-star-forming elliptical galaxy at a redshift of 0.225, which is the location one would expect if the origin of this GRB is through the merger of neutron-star or black-hole binaries. The X-ray afterglow was weak and faded below the detection limit within a few hours; no optical afterglow was detected to stringent limits, explaining the past difficulty in localizing short GRBs.