[vsnet-grb-info 17618] GRB 160221A: GROND upper limits

[GCN Circulars]

TITLE:   GCN CIRCULAR
NUMBER:  19054
SUBJECT: GRB 160221A: GROND upper limits
DATE:    16/02/22 15:52:10 GMT
FROM:    Thomas Kruehler at MPE Garching  <kruehler at mpe.mpg.de>

J. Bolmer, T. Kruehler, J. Greiner (all MPE Garching) report on behalf
of the GROND team:

We observed the field of the INTEGRAL GRB 160221A (Mereghetti et al.,
GCN #19046) simultaneously in g'r'i'z'JHK with GROND (Greiner et al.
2008, PASP 120, 405) mounted at the 2.2m MPG telescope at ESO La Silla
Observatory (Chile).

Observations started at 05:12 UT on 2016-02-22, 5.4 hrs after the GRB
trigger. They were performed at an average seeing of 1.0" and at an
average airmass of 1.4.

No source within the Swift-XRT error circle (Melandri et al.,
GCN #19050) is detected. Based on 48.0 min of exposure in g'r'i'z'
and 43.3 min in JHK, at a mid-time of 06:43 UT, we derive the
following preliminary upper limits:

g' > 23.6 mag
r' > 24.3 mag
i' > 23.4 mag
z' > 23.4 mag
J  > 21.8 mag
H  > 21.1 mag
K  > 20.0 mag

Given limits are in the AB system and calibrated against GROND
zeropoints as well as 2MASS field stars. No correction for the expected
Galactic foreground extinction corresponding to a reddening of
E_(B-V)=0.26 mag in the direction of the burst (Schlafly &
Finkbeiner 2011) has been applied.