[vsnet-grb-info 7551] GRB 090407: GROND upper limits

[GCN Circulars]

TITLE:   GCN CIRCULAR
NUMBER:  9109
SUBJECT: GRB 090407: GROND upper limits
DATE:    09/04/08 02:19:56 GMT
FROM:    Paulo M. J. Afonso at MPE  <pafonso at mpe.mpg.de>

P. Afonso, F. Olivares, J. Greiner and T. Kruehler (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 090407
(H. Ziaeepour et al. 2009, GCN #9101) simultaneously in the g'r'i'z'JHK
bands. 

Observations started on April 7, at 23:34 UTC (13.1 h after the burst)
and lasted for 87 minutes. 

In stacked images of 24 min total integration time in griz and 20 min in 
JHK, we do not detect any new object inside the enhanced XRT error circle
(Evans et al., GCN #9105), down to the following limiting magnitudes
(all in the AB system): 

g' > 23.7
r' > 24.1
i' > 23.5
z' > 23.3
J  > 21.6
H  > 21.0
K  > 20.4 

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 0.07 mag.