[vsnet-grb-info 9964] GRB 101117B: GROND Upper limits

[GCN Circulars]

TITLE:   GCN CIRCULAR
NUMBER:  11421
SUBJECT: GRB 101117B: GROND Upper limits
DATE:    10/11/22 19:05:49 GMT
FROM:    Jonny Elliott at MPE/GROND  <jonnyelliott at mpe.mpg.de>

J. Elliott, R. Filgas, J. Greiner, P. Schady and T. Kruehler (all MPE
Garching) report
on behalf of the GROND team:

We observed the field of GRB 101117B (Swift trigger 438675; Wolf et al.,
GCN #11411) simultaneously in g'r'i'z'JHK with GROND (Greiner et al. 2008,
PASP 120, 405) mounted at the 2.2 m MPI/ESO telescope at La Silla
Observatory (Chile).

Observations started at 05:15 UT on November 19, 34 hours after the GRB
trigger, and have total exposure of 6003 s in g'r'i'z' and  4800 s in JHK.
They were performed at an average seeing of 2.0" and at an average airmass
of 1.8.

We do not detect a source within the UVOT error circle reported by Holland
& Wolf (GCN #11420) down to the following 3 sigma upper limits (all in
AB):

g' > 23.7

r' > 23.8

i' > 23.5

z' > 23.3

J > 21.7,

H > 21.2 and

K > 20.4

The given limits are derived based on calibrating the images against GROND
zeropoints and 2MASS field stars and are not corrected for the Galactic
foreground extinction corresponding to a reddening of E_(B-V)= 0.38 in the
direction of the burst (Schlegel et al. 1998).