GCN Circular 22031
Subject
GRB 171020A: Confirmation of OT fading
Date
2017-10-21T03:32:12Z (7 years ago)
From
Moskvitin Alexander at SAO RAS <mosk@sao.ru>
A. Moskvitin (SAO RAS), O. Spiridonova (SAO RAS), A. Volnova (IKI RAS)
We observed the field of GRB 171020A (Page et al., GCN 22028)
with the 1-m telescope of SAO RAS, Zeiss-1000 on 2017.10.20,
starting at 23:18 UT, i.e. ~11 minutes after the trigger.
The OT (Malesani et al., GCN 22029) is clearly detected
in the individual 300 sec. frames. The coordinates of OT:
R. A. = 02:36:59.62; Dec. = +15:12:15.6 (J2000).
Date UT start t - T0 Filter Exp. OT Err. UL
(mid, days) (s)
2017.10.20 23:18:05 0.02016 Rc 6*300 20.9 +/- 0.1 22.3
23:55:27 0.04827 Rc 7*300 21.5 +/- 0.1 22.5
The temporal decay slope is about -0.3, F ~ (t-T0)^alpha.
The calibration were made against the nearby USNO-B1.0 stars
(R2 magnitudes):
1051-0026883 02:37:00.38 +15:11:09.6 18.59
1052-0027787 02:36:57.49 +15:12:36.8 16.62
1052-0027776 02:36:50.26 +15:12:39.8 18.15