GCN Circular 20080
Subject
GRB 161017A: LT optical observations
Date
2016-10-19T08:29:40Z (8 years ago)
From
Cristiano Guidorzi at Ferrara U,Italy <guidorzi@fe.infn.it>
C. Guidorzi (U. Ferrara), S. Kobayashi, I.A. Steele (LJMU), C.G. Mundell
(U. Bath), A. Gomboc (U. Nova Gorica), N.R. Tanvir (U. Leicester) on
behalf of a large collaboration report:
The 2-m Liverpool Telescope observed Swift GRB161017A (Troja et al., GCN
20064) in the SDSS r and i filters on October 19, from 03:45 to 05:37 UT
(mid time~1.45 days since the GRB). We clearly detect the optical
afterglow (Yurkov et al. GCN 20063; Troja et al. GCN 20064; de
Ugarte-Postigo et al. GCN 20069; Fujiwara et al GCN 20070; Melandri et
al. GCN 20071) with the following values, as calibrated against nearby
SDSS stars:
Mid Time Exposure Filter Magnitude
(days) (s)
-------------------------------------------------------
1.42 5x120 SDSS-R 20.02 +- 0.03
1.42 5x120 SDSS-I 19.80 +- 0.03
-------------------------------------------------------
Compared with our previous report (Guidorzi et al. GCN 20072), we
estimate an average power-law decay index alpha~1.3 between 0.68 and
1.45 days post burst.