[vsnet-grb-info 21614] GRB 190114B: NOT optical counterpart

[GCN Circulars]

TITLE:   GCN CIRCULAR
NUMBER:  23713
SUBJECT: GRB 190114B: NOT optical counterpart
DATE:    19/01/15 12:53:20 GMT
FROM:    Jonatan Selsing at DARK/NBI  <jselsing at dark-cosmology.dk>

J. Selsing (DAWN/NBI and DAWN/DTU), A. de Ugarte Postigo (HETH/IAA-CSIC
and DARK/NBI), and S. Dyrbye (NOT), report on behalf of a larger
collaboration:

We have observed the optical afterglow of GRB GRB190114B (Siegel et al.,
GCN 23686; Goad et al., GCN 23691) at the 2.5-m Nordic Optical Telescope
(NOT). We have obtained an griz-band imaging sequence using the ALFOSC
instrument, with 3x300s exposure in gri-band and 5x200s in z-band.
Observations began at 01:51:42 UT, on the night of the 14th of January,
6.3 hr after the BAT trigger. 

In the images we confirm the detection of the optical counterpart in
Fernandez-Garcia et al. (GCN 23694) and Pozanenko et al. (GCN 23696) and
report further fading. The source is located at:

RA (J2000.0) = 11:39:29.823
DEC (J2000.0) = +18:53:28.19

with the astrometric solution calibrated against the 2MASS catalog. 

We calibrate the photometric zeropoints against the Pan-STARRS catalog
and calculate the following magnitudes for the optical counterpart:

g = 21.61 +- 0.13 AB mag 
r = 21.15 +- 0.09 AB mag 
i = 20.96 +- 0.04 AB mag 
z = 20.59 +- 0.08 AB mag