GCN Circular 10304
Subject
GRB 091231: GROND NIR observations
Date
2010-01-01T10:35:38Z (15 years ago)
From
Sylvio Klose at TLS Tautenburg <klose@tls-tautenburg.de>
R. Filgas (MPE Garching), S. Klose (TLS 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 at La Silla Observatory (Chile), started
follow-up NIR observations of GRB 091231 (Markwardt et al. 2009, GCN
10301) on Jan 1, at 9:04 UT (about 15 hrs after the burst, shortly before
sun rise).
We could not detect the afterglow candidate reported by Holland et al.
(2009; GCN 10303). Based on a 4 min exposure, we estimate the following
preliminary upper limits (in the Vega system):
J > 16.7
H > 16.3
K > 15.2
using GROND zeropoints and the 2MASS catalog.
Due to visibility constraints of the field from La Silla, no earlier
observations were possible.