[vsnet-grb-info 20438] GRB 180325A: prompt LT observations

[GCN Circulars]

TITLE:   GCN CIRCULAR
NUMBER:  22534
SUBJECT: GRB 180325A: prompt LT observations
DATE:    18/03/25 03:05:01 GMT
FROM:    Cristiano Guidorzi at Ferrara U,Italy  <guidorzi at fe.infn.it>

C. Guidorzi (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 
180325A (Troja et al. GCN 22532) on March 25, 01:55:25 UT (143 seconds 
since the GRB trigger time) with the RINGO3 polarimeter and the IO:O 
camera in the SDSS-R filter. We clearly detect the optical afterglow 
(Troja et al.) with the following magnitude:

Mid Time from GRB  Exposure       Filter       Magnitude (AB)
(min)              (s)
-------------------------------------------------------------
35.1               6x10           SDSS-R       19.02 +- 0.05
-------------------------------------------------------------

as calibrated against nearby SDSS objects.