TITLE:   GCN CIRCULAR
NUMBER:  23814
SUBJECT: GRB 190129B: GROND possible host candidate
DATE:    19/01/30 09:30:29 GMT
FROM:    Jan Bolmer at MPE/Garching  <jan@bolmer.de>

J. Bolmer (MPE, Garching) and H. Steinle report:

We observed the field of the extremely bright GRB 190129B (detected by Konus-Wind, INTEGRAL,
and Mars-Odyssey; Hurley et al., GCN #23808) simultaneously in g'r'i'z'JHK with GROND
(Greiner et al. 2008, PASP 120, 405) mounted at the 2.2 m MPG telescope at the ESO
La Silla Observatory (Chile).

Observations started at 07:38 UT on 30th January, around 19.5 hours after the GRB trigger.
They were performed at an average seeing of 1.8" and at an average airmass of 2.1. 

We found a faint source at the edge of the XRT error circle reported by LaPorte et al.
(GCN #23813) at:

RA (J2000.0) = 07:49:50.81
DEC (J2000.0) = +00:56:03.8

with an uncertainty of 1.5" in each coordinate.

This source is already visible in the the PanSTARRS images and might
therefore be the host or an unrelated foreground galaxy.

Based on 7.7 min of exposure in g'r'i'z', and 8.0 min in JHK, we report the
following preliminary AB magnitudes:  

g < 23.0 mag
r = 22.7 +/- 0.3 mag
i = 21.8 +/- 0.3 mag
z = 21.7 +/- 0.4 mag
J = 20.4 +/- 0.4 mag
H = 19.1 +/- 0.2 mag
K = 19.0 +/- 0.4 mag

The above magnitudes are calibrated against SDSS and 2MASS and are not corrected
for the expected Galactic foreground extinction corresponding to a reddening
of E_(B-V)=0.08 in the direction of the burst (Schlafly & Finkbeiner 2011).