GCN Circular 8959
Subject
GRB 090307: GROND Upper Limits
Event
Date
2009-03-09T13:45:36Z (17 years ago)
From
Christian Clemens at MPE <cclemens@mpe.mpg.de>
A. C. Updike (Clemson University), C. Clemens, J. Greiner and P. Afonso (MPE
Garching) report on behalf of the GROND team:
We observed the field of GRB 090307 (Swift trigger 345551; Barthelmy et al.,
GCN #8945) simultaneously in g'r'i'z'JHK with GROND (Greiner et al. 2008,
PASP 120, 405) mounted at the 2.2 m ESO/MPI telescope at La Silla Observatory
(Chile).
Observations started at 05:06 UT on March 7, 80 min after the GRB trigger, and
continued for 66 min. They were performed at an average seeing of 1.2" and at
an average airmass of 1.8.
We do not detect a source within the Swift-XRT error circle reported by Evans
et al. (GCN #8946) down to (all in AB system)
g' > 23.3,
r' > 23.7,
i' > 23.2,
z' > 22.9,
J > 21.7,
H > 21.2 and
K > 20.3.
The given limits are derived based on calibrating the images against GROND
zeropoints and 2MASS field stars and are not corrected for the Galactic
foreground extinction corresponding to a reddening of E_(B-V)= 0.528 in the
direction of the burst (Schlegel et al. 1998).