[vsnet-grb-info 20507] GRB 180404A: LCO FTS observations

[GCN Circulars]

TITLE:   GCN CIRCULAR
NUMBER:  22603
SUBJECT: GRB 180404A: LCO FTS observations
DATE:    18/04/05 09:36:04 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:

We began observing Swift GRB180404A (Gropp et al. GCN 22589) on April 4, 
09:30 UT (0.36 days post burst) with the LCO 2-m Faulkes Telescope South 
unit in Siding Springs in the SDSS-R filter. We marginally detect the 
optical afterglow (Gropp et al.; Selsing et al. GCN 22591) with the 
following magnitude:

Mid time since GRB     Exp        Filter         Magnitude
(days)                 (s)
-------------------------------------------------------------
0.37                   5x120      SDSS-R         21.3 +- 0.3
-------------------------------------------------------------

as calibrated against nearby USNO UCAC4 objects.