TITLE: GCN CIRCULAR NUMBER: 31390 SUBJECT: GRB 220101A: Mondy optical observations DATE: 22/01/05 13:03:41 GMT FROM: Alexei Pozanenko at IKI, Moscow S. Belkin (IKI, HSE), A. Pozanenko (IKI), E. Klunko (ISTP), N. Pankov (HSE) report on behalf of GRB IKI FuN: We observed Swift GRB 220101A (Tohuvavohu, et al., GCN 31347) also detected by Fermi/LAT (M. Arimoto et al. 2022, GCN 31350), AGILE (A. 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 2022-01-04 (UT) 15:16:32. We detect the optical 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). Preliminary photometry of the afterglow in a stacked image is following Date UT start t-T0 Filter Exp. OT Err. UL(3sigma) (mid, days) (s) 2022-01-04 12:36:19 3.33083 R 30*120 21.50 0.12 23.1 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 We searched for the nearest galaxy in catalogs. The nearest galaxy was found in Legacy Survey 1.5 arcsec apart from afterglow UVOT position with r=23.98, z=21.33 and not detected in g-filter (Brick: 0013p317, Objid: 4276). The galaxy is not presented in SDSS and PS1 catalogs. This red galaxy might be a host galaxy of GRB 220101A, in this case the distance from the source to the center of the galaxy will be about 10 kpc at redshift z = 4.618 (Fu et al., GCN 31353; Fynbo et al., GCN 31359; Tomasella et al., GCN 31363).