[vsnet-grb-info 13900] GRB 130912A: GROND observations

[GCN Circulars]

TITLE:   GCN CIRCULAR
NUMBER:  15214
SUBJECT: GRB 130912A: GROND observations
DATE:    13/09/12 11:49:50 GMT
FROM:    Vladimir Sudilovsky at MPE  <vsudilov at mpe.mpg.de>

M. Tanga (MPE Garching), S. Klose (TLS Tautenburg), V. Sudilovsky
(MPE Garching), R. Filgas (IEAP Prague), J. Greiner (MPE Garching)
report on behalf of the GROND team:

We observed the field of GRB 130912A (Swift trigger 570465; D'Elia et al.
2013, GCN #15212) simultaneously in g'r'i'z'JHK with GROND (Greiner et al.
2008, PASP 120, 405) mounted at the 2.2 m MPG/ESO telescope at La Silla
Observatory (Chile).

Observations started at 08:50 UT on 12 Sep 2013, 16 min after the GRB
trigger. At the northern edge of the r=2.2 arcsec XRT error circle (D'Elia
et al., GCN #15173) we detect a faint source at coordinates

RA (J2000)   = 03:10:22.23
Dec. (J2000) = 13:59:48.7

with an error of 0".3 arcseconds.

However, the object seems to be constant over the first hour of
our observations, with a preliminary magnitude of r' = 22.0+-0.2 mag,
calibrated against the GROND zeropoint. Given the constant flux,
this might be the host galaxy of GRB 130912A.