[vsnet-grb-info 9520] GRB 100725A: GROND upper limits

[GCN Circulars]

TITLE:   GCN CIRCULAR
NUMBER:  10991
SUBJECT: GRB 100725A: GROND upper limits
DATE:    10/07/26 02:05:22 GMT
FROM:    Felipe Olivares Estay at MPE  <felipe at mpe.mpg.de>

F. Olivares E. (MPE Garching), S. Klose (Tautenburg), and J. Greiner
(MPE Garching) report on behalf of the GROND team:

GROND (Greiner et al. 2008, PASP 120, 405), the 7-channel imager
mounted at the 2.2m ESO/MPI telescope on La Silla, started follow-up
observations of GRB 100725A (Markwardt et al. 2010, GCN 10979) on July
25 at 23:05 UT (about 16 hrs after the trigger).

With a total integration time of 24.4 min in the optical and 20 min in
the nIR, we do not detect any source within the 1.8-arcsec XRT error
circle (Evans et al. 2010, GCN 10985) down to the following upper
limits (AB system):

g' > 22.8
r' > 23.3
i' > 23.1
z' > 22.9
J  > 21.7
H  > 21.1
K  > 20.4,

The given limits are calibrated againt GROND zeropoints and 2MASS
field stars and are not corrected for the Galactic foreground
extinction corresponding to a reddening of E(B-V)= 0.052 in the
direction of the burst (Schlegel et al. 1998).