TITLE:   GCN CIRCULAR
NUMBER:  7860
SUBJECT: GRB 080603A: optical observations
DATE:    08/06/07 22:52:28 GMT
FROM:    Alexei Pozanenko at IKI, Moscow  <apozanen@iki.rssi.ru>

V. Rumyantsev (CrAO),  A. Pozanenko (IKI) report on behalf of larger GRB 
follow-up collaboration:

We observed  a field of  INTEGRAL GRB 080603A (Paizis et al., GCN 7790) in 
R-band on June 06 between (UT) 22:32 - 23:55 with  Zeiss-1000 (Simeiz) 
telescope of CrAO observatory.   Extended object is found ~1" south from the 
position of optical afterglow (Gomboc et al., GCN 7788; Chornock  et al., 
GCN 7789), and the position of the extended object is consistent with 
coordinates reported by Kuin et al. (GCN 7804). Therefore, we suggest it as 
a host galaxy of  080603A.

Based on  USNOB1.0 star with ID 1527-0313986 at RA = 18:37:55.186, Dec. 
+62:45:32.28 (R1 = 16.74)  we estimated brightness of  the extended object:

UT,       Exposure,   R_mag, UL
(mid time)

3.496  41x120  21.90  +/- 0.17  22.85

If the extended source is the host galaxy then contamination by the host can 
explain slow decay of light curve noted by Kann et al. (GCN 7822).

A combined image can be found at
http://grb.rssi.ru/GRB080603A/GRB080603A_2080606.gif

The message may be cited.