GCN Circular 31422
Subject
GRB 220107A: SAO RAS optical observations
Date
2022-01-09T20:00:03Z (2 years ago)
From
Moskvitin Alexander at SAO RAS <mosk@sao.ru>
A. Moskvitin (SAO), A. Medvedev (SAO), A. Pozanenko (IKI)
and N. Pankov (HSE) on behalf of larger GRB follow-up team report:
We observed the field of GRB 220107A (The Fermi GBM team, GCN 31399;
Kunzweiler et al. GCN 31400; DeLaunay et al. GCN 31402; Suresh et al.,
GCN 31408) with the SAO RAS 1-m telescope Zeiss-1000 + CCD-photometer
in BVRc bands on January 9.
The OT (Hosokawa et al. GCN 31413; Siegel GCN 31415; Zhu et al.
GCN 31416; Pankov et al., GCN 31419) is detected in stacked images
in each filter. Preliminary photometry of the afterglow is as follows.
UT start -- UT end T_mid-T0, d Filter Exp., s mag +/- err
02:19:16 -- 03:00:13 1.4960 Rc 5 x 300 20.41 +/- 0.03
03:01:27 -- 03:18:33 1.5170 V 3 x 300 20.97 +/- 0.06
03:19:40 -- 03:36:26 1.5295 B 3 x 300 22.08 +/- 0.18
Photometry is based on nearby SDSS-DR12 stars
(magnitudes are converted with the Lupton 2005 transformations).
J2000.0 coordinates B V R
11:19:13.93 +34:08:38.8 16.244 15.691 15.363
11:19:13.74 +34:11:49.6 18.811 17.880 17.327
11:19:12.27 +34:11:18.1 18.959 18.506 18.241