[vsnet-grb-info 13953] GRB 130925A: Swift/UVOT Detection of the Host Galaxy

[GCN Circulars]

TITLE:   GCN CIRCULAR
NUMBER:  15267
SUBJECT: GRB 130925A: Swift/UVOT Detection of the Host Galaxy 
DATE:    13/09/27 18:22:43 GMT
FROM:    Stephen Holland at STScI  <sholland at stsci.edu>

S. T. Holland (STScI)
reports on behalf of the Swift/UVOT team:

     Deep Swift/UVOT imaging taken between 157 s and 184.8 ks after
the BAT trigger (Lien et al, 2013, GCNC 15246) shows a faint source at
the location of the GROND detection (Sudilovsky et al. 2013, GCNC
15247).  This source has a preliminary magnitude, on the UVOT
photometric system (Breeveld et al. 2011, AIP Conf. Proc. 1358, 373),
of white = 22.9 +/- 0.3 mag and is detected with a significance of 4.7
sigma.  This magnitude has not been corrected for the expected
extinction due to the Galactic reddening along the line of sight to
this burst of E(B-V) = 0.02 mag (Schlafly et al. 2011, ApJS, 737,
103).  The total white exposure time is 18 ks.  There is no evidence
for variability.

     The probability of finding a galaxy of this apparent luminosity
within the UVOT-enhanced XRT error circle (Evans et al. 2013, GCNC
15251) is 0.01 using the method of Bloom et al. (2002, AJ, 423, 1111).
The positional coincidence and lack of variability suggest that this
is the host galaxy of GRB 130925A.  There is no evidence in the UVOT
data that this source has any extended structure.