[vsnet-grb-info 16842] GRB 150811A: LCOGT-McDonald afterglow detection

[GCN Circulars]

TITLE:   GCN CIRCULAR
NUMBER:  18123
SUBJECT: GRB 150811A: LCOGT-McDonald afterglow detection
DATE:    15/08/11 08:48:37 GMT
FROM:    Jure Japelj at U. of Ljubljana,Slovenia  <jure.japelj at fmf.uni-lj.si>

J. Japelj (U. Ljubljana), C. Guidorzi (U. Ferrara), S. Kobayashi (LJMU)
on behalf of a large collaboration report:

We observed the position of GRB 150811A (Evans et al. GCN Circ.
18119) with the 1-m McDonald telescope (Fort Davis, US), a
member of the Las Cumbres Observatory network. Observations
started on August 11 at 06:13:35 UT, i.e., 127 minutes after
the GRB trigger time and were done with the r' and i' filters.

We detect the optical afterglow (Butler et al. GCN 18120, Zheng
et al. GCN 18121, Kuin et al. 18122) with the magnitude of
r' = 18.4 +- 0.2 at 132 min after the GRB trigger. Magnitude has
been calibrated against nearby USNOB-1 stars.