GCN Circular 30214
Subject
GRB 210610A: CrAO/ZTSH optical observations
Event
Date
2021-06-11T22:36:11Z (4 years ago)
From
Alexei Pozanenko at IKI, Moscow <apozanen@iki.rssi.ru>
S. Belkin (IKI, HSE), A. Pozanenko (IKI), V. Rumyantsev (CrAO), N.
Pankov (IKI, HSE) report on behalf of IKI GRB FuN:
We observed the GRB 210610A (Page et al., GCN 30160) with ZTSH 2.6m
telescope of CrAO observatory on June 10 starting on (UT) 18:29:17, and
June 11 starting on (UT) 18:53:09. The optical afterglow first
reported by UVOT (Page et al., GCN 30160) is clearly detected in each
of a single images in R filter in both epochs.
Preliminary photometry of the afterglow in the first image on June 10,
and combined image on the June 11 is following
Date UT start t-T0 Filter Exp. OT err UL(3 sigma)
(mid, days) (s)
2021-06-10 18:29:17 0.14310 R 1*60 19.47 0.12 20.7
2021-06-11 18:53:09 1.16766 R 12*120 22.19 0.17 23.0
The photometry is based on nearby SDSS DR12 stars
SDSS-DR12_id RA DEC B(Lupton transformation) R(Lupton transformation)
J133717.13+142854.9 204.32139900 +14.48192200 17.8777 17.0295
J133703.62+142832.7 204.26512000 +14.47576300 19.2842 17.7239
J133658.05+142404.4 204.24188500 +14.40123200 20.3290 18.3616
The light curve of can be found in
http://grb.rssi.ru/GRB210610A/GRB210610A_LC.png
Initial power law index of the light curve in the first epoch is about
-0.82, and it is steepening between the two epochs down to -1.03 which
is compatible with broken power-law fit reported by D.A. Kann et al.
(GCN 30211).