A case of mistaken identity? GRB 060912A and the nature of the long-short GRB divide
Levan, A. J., Jakobsson, P., Hurkett, C., Tanvir, N. R., Gorosabel, J., Vreeswijk, P., Rol, E., Chapman, R., Gehrels, N., O'Brien, P. T., Osborne, J. P., Priddey, R. S., Kouveliotou, Chryssa, Starling, R., Vanden Berk, D. and Wiersema, K.. (2007) A case of mistaken identity? GRB 060912A and the nature of the long-short GRB divide. Monthly Notices of the Royal Astronomical Society, Vol.378 (No.4). pp. 1439-1446. ISSN 0035-8711Full text not available from this repository.
Official URL: http://dx.doi.org/10.1111/j.1365-2966.2007.11879.x
We investigate the origin of the GRB 060912A, which has observational properties that make its classification as either a long or short burst ambiguous. Short-duration gamma-ray bursts (SGRBs) are thought to have typically lower energies than long-duration bursts, can be found in galaxies with populations of all ages and are likely to originate from different progenitors to the long-duration bursts. However, it has become clear that duration alone is insufficient to make a distinction between the two populations in many cases, leading to a desire to find additional discriminators of burst type. GRB 060912A had a duration of 6 s and occurred only similar to 10 arcsec from a bright, low-redshift (z = 0.0936) elliptical galaxy, suggesting that this may have been the host, which would favour it being a short burst. However, our deep optical imaging and spectroscopy of the location of GRB 060912A using the Very Large Telescope (VLT) shows that GRB 060912A more likely originates in a distant star-forming galaxy at z = 0.937, and is most likely a long burst. This demonstrates the risk in identifying bright, nearby galaxies as the hosts of given gamma-ray bursts (GRBs) without further supporting evidence. Further, it implies that, in the absence of secure identifications, 'host' type, or more broadly discriminators that rely on galaxy redshifts, may not be good indicators of the true nature of any given GRB.
|Item Type:||Journal Article|
|Subjects:||Q Science > QB Astronomy|
|Divisions:||Faculty of Science > Physics|
|Journal or Publication Title:||Monthly Notices of the Royal Astronomical Society|
|Publisher:||Wiley-Blackwell Publishing, Inc|
|Date:||11 July 2007|
|Number of Pages:||8|
|Page Range:||pp. 1439-1446|
|Access rights to Published version:||Restricted or Subscription Access|
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