GCN Circular 12366
Subject
GRB 110918A: GROND detection of the afterglow candidate
Event
Date
2011-09-20T14:54:05Z (15 years ago)
From
Arne Rau at MPE <arau@mpe.mpg.de>
J. Elliott (MPE Garching), T. Kruehler (DARK/NBI), S. Klose, D. A. Kann
(both TLS Tautenburg), A. Rau and J. Greiner (both MPE Garching) report
on behalf of the GROND team:
We observed the field of the IPN GRB 110918A (Hurley et al., GCN 12357)
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 at September 20, 2011, 02:37 which is roughly 29.2
hr after the trigger. They consisted of a dithered mosaic of 5 tiles
covering the full IPN error box. The X-ray and optical afterglow
candidate reported by Mangano et al. (GCN #12364) and Tanvir et al. (GCN
#12365) however is only covered by the larger field of view of the NIR
channels.
We confirm the presence of a bright NIR source, and estimate a
preliminary AB magnitude of J = 18.7 +/- 0.1 at a midtime of 08:04 UT,
which has been derived by calibrating the field against stars from the
2MASS catalog.