GCN Circular 19144

J. Graham, J. Bolmer, P. Wiseman and J. Greiner (all MPE Garching) report on
behalf of the GROND team:

We observed the field of GRB 160303A (Swift trigger 677495; Beardmore et
al., GCN #19126) simultaneously in g'r'i'z'JHK with GROND (Greiner et al.
2008, PASP 120, 405) mounted at the 2.2m MPG telescope at the ESO La Silla
Observatory (Chile)./
/Observations started at 03:27 UT on 2016-03-04, 16.5h after the GRB
trigger. They were performed at an average seeing of 1.3" and at an
average airmass of 1.6./
/We detect a single source at the edge of the Swift-XRT error circle
reported by Evans et al. (GCN #19132) consistent with the optical 
candidate from de Ugarte Postigo et al. (GCN #19136) and Klose et al. 
(GCN #19142)/
/Based on 66 min of exposure in g'r'i'z' and 60 min in JHK, at a mid-time
of 04:54 UT, we derive the following preliminary magnitudes and upper
limits (in AB system):/
/g' = 24.2 +/- 0.1 mag,
r' = 24.0 +/- 0.1 mag,
i' = 23.9 +/- 0.2 mag,
z' = 23.5 +/- 0.3 mag,
J > 21.1 mag,
H > 20.1 mag, and
K > 19.5 mag./
/Given detections and upper limits are calibrated against SDSS
as well as 2MASS field stars. No correction for the expected Galactic
foreground extinction corresponding to a reddening of E_(B-V)=0.014 mag in
the direction of the burst (Schlafly & Finkbeiner 2011) has been applied.

-- 
Philip Wiseman                 wiseman@mpe.mpg.de
Doctoral Student  	       +49 (0)89 30000-3566
GRB Group	               +49 (0)1605 011752

IMPRS Student Representative

Room X5 1.3.09
Max-Planck-Institute fuer extraterrestriche Physik
Giessenbachstrasse 1
85748 Garching, Germany