[vsnet-grb-info 21405] GRB 181201A: Continued GROND observations show that afterglow is still bright

[GCN Circulars]

TITLE:   GCN CIRCULAR
NUMBER:  23504
SUBJECT: GRB 181201A: Continued GROND observations show that afterglow is still bright
DATE:    18/12/04 15:06:49 GMT
FROM:    Jan Bolmer at MPE/Garching  <jan at bolmer.de>

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

We observed again the field of GRB 181201A (INTEGRAL trigger; Mereghetti et al., GCN #23469)
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 01:01 UT on 4. of Dezember 2018, about three days after the
GRB trigger, and were performed under poor seeing conditions, 2.2'', and at an average
airmass of 2.0.

We still detect the afterglow and based on 17 min of total exposure time,
we measure the following preliminary r'-band AB magnitude, indicating
that the afterglow is still reltively bright, even three days after the
detection of the prompt emission:

r' = 19.43 +/- 0.03 mag

Given magnitude is calibrated against SDSS and not corrected for the
expected Galactic foreground extinction corresponding to a reddening of
E_(B-V)=0.05 in the direction of the burst (Schlafly & Finkbeiner 2011).