[vsnet-grb-info 16058] GRB 150120B: FTN early optical light curve

[GCN Circulars]

TITLE:   GCN CIRCULAR
NUMBER:  17340
SUBJECT: GRB 150120B: FTN early optical light curve
DATE:    15/01/21 14:51:41 GMT
FROM:    Cristiano Guidorzi at Ferrara U,Italy  <guidorzi at fe.infn.it>

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

The 2-m Faulkes Telescope North observed Swift GRB150120B
(D'Elia et al. GCN 17314; Perley GCN 17315) from 18 to 100 minutes
since the burst trigger time with SDSS r and i filters.
Both light curves are fitted with a power-law with a decay index
alpha=0.8 +- 0.1. A comparison with the observations at later times
(Perley GCN 17335; Wiseman et al. GCN 17336; Pandey GCN 17337;
Xin et al. GCN 17339) suggests that a steepening of the decay
must have occurred between ~2e4 and ~6e4 s.