[vsnet-grb-info 8039] GRB 090625B: GROND upper limits

[GCN Circulars]

TITLE:   GCN CIRCULAR
NUMBER:  9578
SUBJECT: GRB 090625B: GROND upper limits
DATE:    09/06/26 09:29:18 GMT
FROM:    Thomas Kruehler at MPE/MPI  <kruehler at mpe.mpg.de>

T. Kruehler, F. Olivares, and J. Greiner (all MPE Garching) report on behalf
of the GROND team:

We observed the field of GRB 090625B (Gotz et al., GCN #9572)
simultaneously in g'r'i'z'JHK with GROND (Greiner et al. 2008, PASP 120,
405) mounted at the 2.2m MPI/ESO telescope at La Silla Observatory
(Chile).

Observations started on 26 June 2009 at 03:58 UT, 14.5 hours after the
burst, continued until 05:58 UT and were performed under variable sky
conditions. In stacked images of 75 min total integration time in griz and
60 min in JHK, we do not detect any object within the XRT error circle
(Mao et al., GCN #9573), down to the following limiting magnitudes (all in
the AB system):

g' > 23.6
r' > 23.8
i' > 23.1
z' > 22.7
J  > 21.5
H  > 21.0
K  > 20.5

These upper limits were derived using USNO-B1 and 2MASS field stars as
reference. No correction has been made for the Galactic foreground
extinction corresponding to E(B-V) of 0.02 mag (Schlegel et al., 1998).