[vsnet-grb-info 17174] GRB 151029A: GROND afterglow observations

[GCN Circulars]

TITLE:   GCN CIRCULAR
NUMBER:  18523
SUBJECT: GRB 151029A: GROND afterglow observations
DATE:    15/10/29 09:15:29 GMT
FROM:    Thomas Kruehler at MPE Garching  <kruehler at mpe.mpg.de>

F. Knust, J. Bolmer, T. Kruehler (all MPE Garching), S. Schmidl
(TLS Tautenburg) and J. Greiner (MPE Garching) report:

We observed the field of GRB 151029A (Swift trigger 662086,
Ukwatta et al., GCN 18522)  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 October 29, 2015, 08:33, about
40 minutes after the GRB trigger. Inside the X-ray error
(Ukwatta et al., GCN 18522) circle we detect the UVOT
counterparts at coordinates

RA: 02:34:06.75
Decl: -35:23:08.6

with an error of around 0".5.

At a mean time of October 29, 2015, 08:37 UTC, we measure
the following preliminary AB magnitudes and upper limits of:


g' = 19.9 +- 0.1
r' = 19.7 +- 0.1
i' = 19.7 +- 0.1
z' = 19.7 +- 0.1
J = 19.5 +- 0.2
H > 19.4
K > 19.4

Magnitudes and upper limts are calibrated against GROND zeropoints
and 2MASS field stars and are not corrected for the Galactic
extinction corresponding to a reddening of E_B-V = 0.018 mag
(Schlafly & Finkbeiner 2011) in the direction of the burst.