GCN Circular 7948

C. Clemens, S. Loew, J. Greiner, A. Yoldas, T. Kruehler (all MPE Garching), A. 
Kupcu Yoldas (ESO) and G. Szokoly (Eoetvoes Univ., Budapest) report on behalf 
of the GROND team:

We observed the field of GRB 080707 (Swift trigger 316204; Schady et al., GCN 
#7947
Not found
 
 
) simultaneously in g'r'i'z'JHK with GROND (Greiner et al. 2008, PASP 
120, 405) mounted at the 2.2 m ESO/MPI telescope at La Silla Observatory 
(Chile).

Observations started at 10:00 UT on July 7th, 2008, 92.2 min after the GRB 
trigger, and were performed at an average seeing of 2.2" and at an average 
airmass of 2.6.

We found a faint source within the 2.9'' Swift-XRT error circle at

RA (J2000.0) = 02h 10m 28.40s
DEC (J2000.0) = +33d 06' 34.3''

with an uncertainty of 0.8".

The object is detected in g' band, implying a redshift smaller than 3.5.

Based on the first 4.4 min of effective exposures in g'r'i'z', we estimate 
preliminary magnitudes of

g' ~ 22.1 mag,
r' ~ 21.5 mag,
i' ~ 21.4 mag and
z' ~ 21.2 mag

with typical errors of +/- 0.3. Given magnitudes are calibrated against 
USNO-B1 field stars.

Please note, that no correction for the galactic foreground reddening of 
E(B-V) = 0.1 mag (Schlegel et al., 1998) has been applied.