GCN Circular 12454
Subject
GRB 111018A: GROND Upper Limits
Event
Date
2011-10-19T06:21:50Z (15 years ago)
From
Jochen Greiner at MPI <jcg@mpe.mpg.de>
M. Nardini (Uni. Milano-Bicocca), J. Elliott and J. Greiner (both MPE
Garching) report on behalf of the GROND team:
We observed the field of GRB111018A (Swift trigger 505801; Marhsal et
al., GCN #12450) 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).
Observations started at 23:47 UT on 18 October 2011, 6.35 hours after
the trigger. They were performed at an average seeing of 2.8 and at
an average airmass of 1.9.
Based on images with total exposures of 1500 s in g'r'i'z' and 1200 s
in JHK, we do not detect a source within the Swift-XRT error circle
reported by Goad et al. (GCN #12453) down to (all AB):
g' > 23.2,
r' > 23.5,
i' > 22.5,
z' > 22.2,
J > 20.0,
H > 18.9,
K > 18.6
Given magnitudes are calibrated against GROND zeropoints as well as
2MASS field stars and are not corrected for the expected Galactic
foreground extinction corresponding to the heavy reddening of
E(B-V)=2.16 in the direction of the burst (Schlegel et al. 1998).