[vsnet-grb-info 20508] GRB 180404B: LCO FTS observations

[GCN Circulars]

TITLE:   GCN CIRCULAR
NUMBER:  22604
SUBJECT: GRB 180404B: LCO FTS observations
DATE:    18/04/05 09:36:43 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 GRB180404B (LaPorte et al. GCN 22590) on April 
4, 08:50 UT (mid time of 0.28 days post burst) with the LCO 2-m Faulkes 
Telescope South unit in Siding Springs in the SDSS-I filter. We do not 
detect the optical afterglow (LaPorte et al.; Lipunov et al. GCN 22596) 
down to the following limit:

Mid time since GRB     Exp        Filter         Magnitude
(days)                 (s)
-------------------------------------------------------------
0.28                   5x120      SDSS-I         > 20.2
-------------------------------------------------------------

as calibrated against nearby USNO UCAC4 objects.