[vsnet-grb-info 9426] GRB100625A: GROND confirmation of constant source

[GCN Circulars]

TITLE:   GCN CIRCULAR
NUMBER:  10906
SUBJECT: GRB100625A: GROND confirmation of constant source
DATE:    10/06/29 14:01:16 GMT
FROM:    Paulo M. J. Afonso at MPE  <pafonso at mpe.mpg.de>

GRB 100625A: GROND confirmation of constant source

A. Updike (Clemson University), P. Afonso and J. Greiner (both MPE
Garching) report on behalf of the GROND team:

We observed the field of the short-hard GRB 100625A, discovered by
SWIFT(Holland et al., GCN 10884), simultaneously in g'r'i'z'JHK with GROND
(Greiner et al.2008, PASP 120, 405) mounted at the 2.2 m MPI/ESO telescope
at La Silla Observatory (Chile).

First epoch observations started at 06:13 UT on June 26, 10.7 hours
after the GRB trigger, lasting for about 1 hour and done at high air mass.
We took a second epoch starting at 09:29 UT on June 27 (~38 hrs after the
trigger), lasting also for about 1 hour and done at seeing of ~ 2''.

Within the enhanced XRT-position error circle (Good et al., GCN 10886)
we detect a faint object at a position compatible with the Gemini-South
candidate afterglow (Levan & Tanvir, GCN 10887).

Based on stacked images with a total integration time of 49.6 min in
g'r'i'z' and 40 min for JHK for each epoch, preliminary AB magnitudes
(calibrated with GROND zero points) show that within the errors the object
is constant between our two epochs.

As suggested by the Magellan observations (Berger et al., GCN 10897) our
results also point to the detection of a possible host galaxy.