TITLE:   GCN CIRCULAR
NUMBER:  31398
SUBJECT: GRB 220101A: Continued Mondy optical observations
DATE:    22/01/07 12:25:31 GMT
FROM:    Alexei Pozanenko at IKI, Moscow  <apozanen@iki.rssi.ru>

N. Pankov (HSE), A. Pozanenko (IKI), E. Klunko (ISTP), Belkin (IKI, HSE)
report  on behalf of GRB IKI FuN:

We observed Swift GRB 220101A (Tohuvavohu, et al., GCN 31347) also
detected by Fermi/LAT (Arimoto et al. 2022, GCN 31350), AGILE (Ursi et 
al. 2022, GCN 31354), and Fermi/GBM (Lesage et al. 2022, GCN 31360) with 
AZT-33IK telescope of Sayan observatory (Mondy) starting on 2022-01-06 
(UT) 13:57:13. We detected the afterglow (Tohuvavohu et al., GCN 31347; 
Kuin & Tohuvavohu, GCN 31351; Fu et al., GCN 31353; Hentunen et al., GCN 
31356; Perley et al., GCN 31357; de Ugarte Postigo et al., GCN 31358; 
Fynbo et al., GCN 31359; Vinko et al., GCN 31361; Tomasella et al., GCN 
31363; Mao et al., GCN 31364; Noschese et al., GCN 31366; Mao et al., 
GCN 31368; Guelbenzu, et al., GCN 31370; Strausbaugh et al., GCN 31371, 
D'Avanzo et al., GCN 31373; Strausbaugh et al., GCNs 31383, 31389; 
Dimple et al., GCN 31384; Romanov, GCN 31387; Caballero-Garcia, GCN 
31388; Belkin et al, GCN 31390; Gupta et al, GCN 31394; D'Avanzo et al, 
GCN 31395) in  a stacked image.

Preliminary photometry of the afterglow is following

Date       UT start  t-T0      Filter Exp.   OT    Err.  UL(3sigma)
                      (mid, days)        (s)

2022-01-06 13:57:13   5.38683    R    30*120 22.17 0.18  23.0

The photometry is based on the nearby SDSS-DR12 stars
RA DEC R(Lupton)
00:05:20.64408 +31:45:46.0728 18.562
00:05:34.81464 +31:45:50.5224 15.734
00:05:32.53944 +31:44:51.9396 15.369
00:05:36.69864 +31:44:42.4176 14.677