Could GRB 060614 and its presumed host galaxy be a chance superposition?
COBB B.E., BAILYN C.D., VAN DOKKUM P.G. and NATARAJAN P.
Abstract (from CDS):
The lack of an observed supernova associated with GRB 060614 appears to require a new paradigm for the formation of (a subset of) long-duration GRBs. This requirement is based on the presumed low redshift of the burst, which was inferred from the spatial coincidence of the afterglow with a z=0.125 galaxy. We explore the possibility that this low-redshift galaxy is a chance superposition along the line of sight to GRB 060614. We examine the galaxy distribution of the field of GRB 060614 and find that the probability of a chance association with a galaxy at least as bright as the putative host is only ∼0.5%-1.9%. However, for the current ensemble of ~180 Swift GRBs, it is likely that several such coincidences have occurred, and given the ``nonstandard'' nature of GRB 060614 it is not implausible that this is one such occurrence. Thus, the conclusion that GRB 060614 requires a revision to the formation paradigm for long-duration GRBs should be approached with caution.