TITLE:   GCN CIRCULAR
NUMBER:  23682
SUBJECT: GRB 190114A: GROND detection of the afterglow
DATE:    19/01/14 09:21:12 GMT
FROM:    Jan Bolmer at MPE/Garching  <jan@bolmer.de>

J. Bolmer (MPE, Garching) and P. Schady (Univ. of Bath) report:

We observed the field of GRB 190114A (Swift trigger 883600; LaPorte et al., GCN #23677) 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 ESO
La Silla Observatory (Chile).

Observations started at 03:16 UT on 14th January, around 5 minutes after the GRB trigger. They were performed
at an average seeing of 1.4" and at an average airmass of 1.3. 

We found a faint source within the 1.7 arcsec Swift-XRT error circle reported by Evans et al. (GCN #23681) at

RA (J2000.0) = 4:22:10.58
DEC (J2000.0) = +2:11:28.32

with an uncertainty of 0.25" in each coordinate. 

Based on the first 6.5 min of exposure, we report the following preliminary JHK magnitudes:  

J = 16.41 +/- 0.05 mag
H = 15.88 +/- 0.05 mag
K = 15.53 +/- 0.07 mag

The above magnitudes are calibrated against 2MASS and are not corrected for the expected
Galactic foreground extinction corresponding to a reddening of E_(B-V)=0.19 in the direction
of theburst (Schlafly & Finkbeiner 2011).