[vsnet-grb-info 14589] GRB 140302A: GROND afterglow candidate

[GCN Circulars]

TITLE:   GCN CIRCULAR
NUMBER:  15903
SUBJECT: GRB 140302A: GROND afterglow candidate
DATE:    14/03/02 11:33:18 GMT
FROM:    Sebastian Schmidl at TLS Tautenburg  <schmidl at tls-tautenburg.de>

J. Elliott (MPE Garching), S. Schmidl (TLS Tautenburg), and J. Greiner
(MPE Garching) report on behalf of the GROND team:

We observed the field of GRB 140302A (Swift trigger 589685; Pagani et al.,
GCN #15901) 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 08:21:12 UT on the 2nd March 2014, 8.2 min after
the GRB trigger. They were performed at an average seeing of 1.5" and at
an average airmass of 1.2.

We find a faint point source inside the enhanced XRT error
circle given in Evans et al. (GCN #15902)

RA (J2000.0) = 16:55:26.30
DEC (J2000.0) = -12:52:42.2

with an uncertainty of 0.5" in each coordinate.

Based on a total exposure of 1936 sec in r', at a mid-time of 0.65
hrs after the burst, we measure the following preliminary magnitude (in AB):

r = 23.7 +/- 0.2 mag.

No statement about fading can be made at this stage.

Given magnitude is calibrated against GROND zeropoint and is not
corrected for the expected Galactic foreground extinction corresponding to
a reddening of E_(B-V) = 0.52 mag in the direction of the burst (Schlegel
et al. 1998).