[vsnet-grb-info 7729] GRB 090429B: GROND Observations

[GCN Circulars]

TITLE:   GCN CIRCULAR
NUMBER:  9283
SUBJECT: GRB 090429B: GROND Observations
DATE:    09/04/29 07:58:36 GMT
FROM:    Aybuke Kupcu Yoldas at ESO  <ayoldas at eso.org>

F. Olivares (MPE Garching), A. Kupcu Yoldas (ESO), J. Greiner, T. 
Kruehler, A. Yoldas (both MPE Garching) report on behalf of the GROND team:

We observed the field of GRB 090429B (Swift trigger 350854; Ukwatta et 
al., GCN #9281) 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 05:43 UT, ~13 minutes after the GRB trigger and 
continued until the source reached the 20 deg horizon limit. They are 
performed at an average seeing of 1.2 and at an average airmass of 2.5.

We do not detect any source within the Swift-XRT error circle reported 
by Ukwatta et al. (GCN #9281) down to the following limits (based on 4 
minutes of exposure time, all in AB system):

g' > 23.4 mag
r' > 23.3 mag
i' > 22.4 mag
z' > 21.8 mag
J > 21.5 mag
H > 20.2 mag
K > 19.6 mag

Quoted upper limits have been derived using USNO and 2MASS field stars
as reference.