[vsnet-grb-info 7248] GRB 090117: GROND Upper Limits

[GCN Circulars]

TITLE:   GCN CIRCULAR
NUMBER:  8820
SUBJECT: GRB 090117: GROND Upper Limits
DATE:    09/01/18 04:13:15 GMT
FROM:    Andrea Rossi at TLS Tautenburg  <rossi at tls-tautenburg.de>

A. Rossi (Tautenburg Obs.), F. Olivares (MPE Garching), A. Kupcu Yoldas (ESO), J. Greiner, and A. Yoldas (both MPE Garching) report on behalf
of the GROND team:

We observed the field of GRB 090117 (SuperAGILE trigger, Donnarumma et al. GCN #8817) simultaneously in g'r'i'z'JHK with GROND (Greiner et al. 2008,
PASP 120, 405) mounted at the 2.2m MPI/ESO telescope at La Silla (Chile).
Observations started at 01:40 UT, about 9 hrs after the GRB.

We do not detect any new sources within the 5-sigma Swift/XRT error circle  (Breadmore & Evans, GCN #8818). Note that there is a R~16 magnitude star within the XRT position contaminating the search for the GRB afterglow. Co-added images of the first 8 minutes yield the following specific limits (in AB magnitudes):

g' > 23.7
r' > 24.1
i' > 23.2
z' > 22.2
J > 21.9
H > 20.9
K > 20.3

The magnitudes are calibrated against the GROND zeropoints and 2MASS field stars.