[vsnet-grb-info 15921] GRB 141221A: LCOGT-McDonald optical afterglow observations

[GCN Circulars]

TITLE:   GCN CIRCULAR
NUMBER:  17209
SUBJECT: GRB 141221A: LCOGT-McDonald optical afterglow observations
DATE:    14/12/21 15:07:45 GMT
FROM:    Cristiano Guidorzi at Ferrara U,Italy  <guidorzi at fe.infn.it>

C. Guidorzi, S. Dichiara (U. Ferrara), D. Kopac, A. Gomboc (U. Ljubljana)
on behalf of a larger collaboration report:

The 1-m LCOGT McDonald telescope began observing Swift GRB 141221A
(Sonbas et al. GCN 17206) on Dec 21 at 10:26:35 UT, corresponding
to 2.3 hours after the burst trigger, with SDSS r' and i' filters.
We detect the optical afterglow (Sonbas et al. GCN 17206; Covino
GCN 17208) with i'=20.1 +- 0.3 mag at a mid time of 2.61 hours
post burst (total exposure of 600 s).