GCN Circular 32818
Subject
GRB 221009A: optical observations, SN photometric evidence
Event
Date
2022-10-22T22:47:16Z (3 years ago)
From
Alexei Pozanenko at IKI, Moscow <apozanen@iki.rssi.ru>
S. Belkin (IKI, HSE), A. Moskvitin (SAO RAS), V. Kim (FAI), A. Pozanenko
(IKI), M. Krugov (FAI), R. Uklein (SAO RAS), N. Pankov (HSE) report on
behalf of GRB IKI FuN:
We continue observations of GRB 221009A (Swift J1913.1+1946) (Dichiara
et al., GCN 32632; Kennea and Williams, GCN 32635; Veres et al., GCN
32636; Bissaldi et al., GCN 32636; Svinkin et al., GCN 32641; Piano et
al., GCN 32657; Pillera et al., GCN 32658; Gotz et al., GCN 32660; Xiao
et al., GCN 32661; Frederiks et al., GCN 32668; GCN 32668; Ripa
et al., GCN 32685; Kozyrev et al., GCN 32805). Observations with
AZT-20 telescope of Assy-Turgen observatory obtained on October 20, 21
and TOO photometry with BTA SAO RAS telescope equipped with SCORPIO-2
was obtained on October 16 and 18. The optical afterglow (GCNs 32632,
32635, 32636, 32641, 32657, 32658, 32660, 32666, 32668, 32670, 32671,
32676, 32677, 32678, 32679, 32680, 32683, 32684, 32685, 32686, 32691,
32692, 32693, 32694, 32695, 32700, 32705, 32707, 32709, 32727, 32729,
32730, 32736, 32738, 32739, 32740, 32743, 32746, 32749, 32750; 32752;
32753; 32755; 32758; 32765; 32769; 32771; 32795; 32799; 32803; 32804;
32809; 32811) is detected in combined images of g',r',i' filters.
Preliminary photometry of the afterglow on 2022-10-20/21 obtained in
Assy observatory with AZT-20 telescope is following
Date UT start t-T0 Exp. Filter OT Err. UL(3sigma)
(mid, days) (s) (AB)
2022-10-20/21 n/d 11.55024 59*60 g' 23.7 0.2 24.5
2022-10-21 14:18:18 12.05299 30*60 r' 21.94 0.07 23.9
2022-10-21 14:49:37 12.08516 30*60 i' 20.72 0.11 23.3
The photometry is based on nearby PS1 stars.
The light curve based on our observations can be found in
http://grb.rssi.ru/GRB221009A/GRB221009A_lc_cc_15_cut.png
We observe a bump in the light curve starting on 6th days since trigger.
The light curve is clearly chromatic at the bump. We can assume that
the chromatic bump is a supernova over an afterglow of GRB 221009A
(Belkin et al., GCN 32769).