GCN Circular 14645
Subject
GRB 130427A: optical observations
Event
Date
2013-05-14T20:23:42Z (12 years ago)
From
Alexei Pozanenko at IKI, Moscow <apozanen@iki.rssi.ru>
A. Volnova (IKI), I. Korobtsev (ISTP), E. Klunko (ISTP), A. Pozanenko
(IKI) on behalf of larger GRB follow-up collaboration:
We continue observation of the Swift GRB 130427A (Maselli et al., GCN
14448) with AZT-33IK telescope of Sayan observatory (Mondy). The
afterglow (Elenin et al. GCN 14450, Perley GCN 14451) is clearly
detected. The brightness of the afterglow+host is following:
UT start, t-t0 Filter Exp. OT
(mid, days) (s) (mag.)
2013-05-13T15:20:00 16.3346 R 3600 20.66 +/- 0.06
2013-05-14T14:24:35 17.2968 R 3600 20.63 +/- 0.07
The photometry is based on the same star reported by Rumyantsev et al.
(GCN 14582). After subtraction of a suggested brightness (R, Vega)of
the host galaxy (e.g. Watson et al., GCN 14606; Kann et al., GCN 14631)
from our photometric values, our light curve can be approximated (in
general) by a single power law starting at ~ 0.6 days after burst
trigger. Indeed our early observations suggest some flattening between
6.5 - 13 days (Xu et al., GCN 14597; Kann et al., GCN 14631). It could
be due to a SN or due to a wide bump analogous to bumps observed early
in the light curve. However photometry is still preliminary and more
detailed calibration/intercalibration is necessary.