[vsnet-grb-info 8483] GRB 091003: Lick observations and possible SDSS host galaxy

[GCN Circulars]

TITLE:   GCN CIRCULAR
NUMBER:  9997
SUBJECT: GRB 091003: Lick observations and possible SDSS host galaxy
DATE:    09/10/06 22:17:22 GMT
FROM:    Daniel Perley at U.C. Berkeley  <dperley at astro.berkeley.edu>

D. A. Perley, J. Choi, A. J. L. Morton, and M. Ganeshalingam (UC 
Berkeley) report:

We observed the position of Fermi GRB 091003 (Rau et al., GCN9983) using 
the Nickel 1m telescope at Lick Observatory on the night of 2009-10-06 
(UT) starting at 04:06 for a series of five 600-second exposures in 
R-band.  The afterglow (Starling and Beardmore, GCN 9986; Gronwall and 
Starling, GCN 9987) is marginally detected in the combined frame.

Calibrating to nearby SDSS stars transformed to R-band using the 
equations of Lupton et al. (2005) we estimate a magnitude of

R = 21.2 +/- 0.4  (t_mid = 3.00 days)

This suggests only limited fading since the observations of Wiersama et 
al. (GCN 9995).

Further, we note that a source coincident with this position is detected 
in the SDSS survey imaging.  The object (SDSS J164604.70+363731.1) has a 
magnitude of r = 23.2 and is classified as a star, but could represent 
the host galaxy of this event.  A low redshift would also be consistent 
with the absence of absorption signatures in the spectrum of Wiersema et 
al. and with the Swift UVW2 detection (Pritchard et al., GCN 9990).  We 
encourage further observations, in particular additional spectroscopy, 
of this object.