GCN Circular 33240
N. Pankov (HSE, IKI), V. Kim (FAI, Pulkovo Observatory), A. Pozanenko (IKI), M. Krugov (FAI), S. Belkin (IKI) report on behalf of GRB IKI FuN: We observed the optical source ZTF23aaarlti/AT2023avj (Wang et al., GCN 33226) with AZT-20 telescope of Assy-Turgen observatory starting on 2023-01-28 (UT) 13:40:30. We clearly detect the optical source (Wang et al., GCN 33226; Pankov et al., GCN 33227) which is also detected in radio (Perley et al., GCN 33233) and in X-ray (Ho et al., GCN 33238). Preliminary photometry of the optical afterglow in a stacked image is following Date UT start MJD Exp. Filter OT Err. UL(3sigma) (mid, days) (s) 2023-01-28 13:40:30 59972.5698 90*60 r'(AB) 23.10 0.15 24.1 The photometry is based on nearby PS1 stars.