[vsnet-grb-info 16802] GRB 150727A: LCOGT-Cerro Tololo observations

[GCN Circulars]

TITLE:   GCN CIRCULAR
NUMBER:  18083
SUBJECT: GRB 150727A: LCOGT-Cerro Tololo observations
DATE:    15/07/28 10:03:02 GMT
FROM:    Simone Dichiara at Ferrara U/Italy  <dichiara at fe.infn.it>

S. Dichiara, C. Guidorzi (U. Ferrara), C.G. Mundell (U. Bath),
S. Kobayashi (LJMU), A. Gomboc (U. Ljubljana) on behalf of
a large collaboration report:

Using a 1-m LCOGTN telescope in Cerro Tololo (Chile),
we began observing GRB 150727A (Cenko et al. GCN 18076;
Younes et al. GCN 18081) on July 28 01:23:01 UT
(~6.3 hours after the burst trigger) with r' and i' filters.

We did not detect the UVOT counterpart (Cenko et al. 2015, GCN 18076)
down to the following limit:

Mid time from  Total Exp   Filter    Magnitude
trigger (hr)   (s)
-------------------------------------------------
6.71           120x10        r'        > 18.9
6.76           120x9         i'        > 16.5
-------------------------------------------------

Values have been calibrated against nearby USNOB-1 stars
(R2 and I).