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GCN Circular 9395

GRB090518: GROND upper limits
2009-05-19T02:37:52Z (15 years ago)
Andrea Rossi at TLS Tautenburg <>
A. Rossi (Tautenburg), P. Afonso 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), observed the field of GRB 090518
(P. Evans et al. 2009, GCN #9386) simultaneously in the g'r'i'z'JHK
bands. Observations started on May 18, at 23:01 UTC, 21.1 h after the burst.
In stacked images of 49 min total integration time in griz and 40 min in
JHK, we do not detect any new object inside the enhanced XRT error circle
(P. Evans et al., GCN #9387), down to the following limiting magnitudes
(all in the AB system):

g' > 24.5
r' > 24.9
i' > 24.2
z' > 23.8
J  > 22.4
H  > 22.1
K  > 21.2

The upper limits have been obtained using GROND zero points and 2MASS
field stars as reference. No correction has been made for the expected
extinction corresponding to E(B-V) of 0.04 mag.
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