TITLE: GCN CIRCULAR NUMBER: 12893 SUBJECT: GRB 111225A: optical observations DATE: 12/01/21 22:04:47 GMT FROM: Alexei Pozanenko at IKI, Moscow A.Volnova (SAI MSU), E. Klunko (ISTP), M. Andreev, A. Sergeev (Terskol Branch of INASAN), A. Pozanenko (IKI) on behalf of larger GRB follow up collaboration report: We observed the field of GRB 111225A (Siegel et al., GCN 12720) with AZT-33IK telescope of Sayan observatory (Mondy) on Dec. 25 between (UT) 17:37:41 - 18:25:58 in R filter under mean seeing (FWHM) of about 2.0". We also observed the field with Zeiss-2000 telescope of Mt. Terskol observatory on Dec. 26 between (UT) 17:37:23-18:46:37 in BRI filters under poor seeing (FWHM) of about 4.4". On stacked images of both epochs we did not find an optical counterpart (Siegel et al., GCN 12720; Klotz et al., GCN 12722; Adria et al., GCN 12723; Wren et al., GCN 12803). The photometry is based on the USNO-B1.0 star 1415-0025726 (J2000) 00:52:35.11 +51:33:58.9, assuming B = 17.56, R =16.50, I = 16.20: T0+, Filter, Exposure, OT, UL(3 sigma), Telescope (mid, d) (s) 0.63278 R 24 x 120 n/d 22.5 AZT-33IK 1.58789 B 10 x 90 n/d 22.0 Zeiss-2000 1.60285 R 10 x 90 n/d 21.5 Zeiss-2000 1.61677 I 10 x 90 n/d 20.5 Zeiss-2000 Upper limits above are consistent with upper limits of R~22.5 reported by Sonbas et al. (GCN 12740) and observations of the afterglow at R ~ 23.2 on ~ 1day after burst trigger (Cenko et al., GCN 12733). Taking into account the positive detection of the afterglow on 3.7590 days at R~22.5 (Rumyantsev et al., GCN 12793) one can suggest a strong rebrightening of the afterglow which is a rare case of late afterglow (3.7590 days) of an apparently nearby burst (cf. UVOT optical detection in uvw2 filter (Siegel, GCN 12735).