[vsnet-grb-info 7570] GRB 090410: GROND upper limits

[GCN Circulars]

TITLE:   GCN CIRCULAR
NUMBER:  9128
SUBJECT: GRB 090410: GROND upper limits
DATE:    09/04/14 16:18:34 GMT
FROM:    Jochen Greiner at MPI  <jcg at mpe.mpg.de>

P. Afonso, T. Kruehler, A. Rau 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 observations of GRB 090410 (Grupe et al. 2009, GCN #9122) on April 
11, at 10:17 UTC (17.3 h after the burst). In addition, a second epoch of 
imaging was obtained, which started on April 12, 10:10 UTC.

Observations were performed at high airmass (~2.5) and limited to a total 
of 4 min exposures in each J, H and K in both epochs because of Sun 
constraints.

We do not detect any new object with respect to 2MASS inside the enhanced 
BAT error circle (Barthelmy et al. 2009, GCN #9123), and 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):

J > 19.1 mag
H > 19.0 mag
K > 18.1 mag

The upper limits have been obtained using 2MASS field stars as reference. 
The given magnitudes are not corrected for the expected Galactic foreground 
extinction of E(B-V) of 0.05 mag.