GCN Circular 9178
Subject
GRB 090418B: GROND observations
Date
2009-04-20T22:22:31Z (15 years ago)
From
Jochen Greiner at MPI <jcg@mpe.mpg.de>
P. Afonso (MPE), S. Klose (Tautenburg), T. Kruehler and J. Greiner (both
MPE Garching), report on behalf of the GROND team:
GROND (Greiner et al. 2008, PASP 120, 405), mounted at the 2.2m ESO/MPI
telescope at La Silla Observatory (Chile) started follow-up observations of
GRB 090418B (Copete et al., GCN #9150) on April 19, at 03:00 UTC (18.0 h
after the burst). In addition, a second epoch of imaging was obtained,
which started on April 20, 04:05 UTC.
Similar to Guidorzi et al. (2009, GCN #9176) we do not detect any new object
with respect to SDSS/2MASS inside the BAT error circle. Image subtraction
between the two epochs does not reveal any obvious variable source. Upper
limits from the first observation are as follows (all in the AB system):
g' > 23.8 mag
r' > 24.0 mag
i' > 23.2 mag
z' > 23.0 mag
J > 22.0 mag
H > 21.4 mag
K > 20.8 mag
Quoted upper limits have been derived using SDSS and 2MASS field stars as
reference.