[vsnet-grb-info 20618] GRB 180512A: LT prompt observations

[GCN Circulars]

TITLE:   GCN CIRCULAR
NUMBER:  22716
SUBJECT: GRB 180512A: LT prompt observations
DATE:    18/05/13 08:31:12 GMT
FROM:    Cristiano Guidorzi at Ferrara U,Italy  <guidorzi at fe.infn.it>

C. Guidorzi, R. Martone (U. Ferrara), S. Kobayashi (LJMU), C.G. Mundell 
(U. Bath), A. Gomboc (U. Nova Gorica), I.A. Steele (LJMU) on behalf of a 
large collaboration report:

The 2-m Liverpool Telescope automatically began observing Swift GRB 
180512A (Deich et al. GCN 22710) on May 12, 22:07:15 UT (5.5 minutes 
since the GRB) with the RINGO3 polarimeter and the IO:O camera in the 
SDSS-R filter. Within the enhanced XRT error circle (Evans et al. GCN 
22715) we do not detect any optical counterpart down to the following 
magnitude:

Mid time since GRB     Exp        Filter         Magnitude
(hrs)                  (s)
-----------------------------------------------------------
0.64                  6x10       SDSS-R          > 20.8
-----------------------------------------------------------

as calibrated against nearby SDSS objects.