TITLE: GCN CIRCULAR NUMBER: 38913 SUBJECT: EP250111a: Mondy optical observation DATE: 25/01/11 23:14:49 GMT FROM: Alexei Pozanenko at IKI, Moscow grb.alex@gmail.com

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

We performed optical observations of the field of EP250111a (Zhao et. al, GCN 38905; Kennea et. al, GCN 38910) in the R filter with the 1.5-meter AZT-33IK telescope of the Sayan Solar Observatory (Mondy). The observations started on 2025-01-11 11:57 UT, i.e. ~0.46 days since trigger. We detect the optical source proposed by Fu et. al, GCN 38906 as an optical transient of EP250111a. Preliminary photometry of the source is the following:

Date UT start t-T0 Exp. Filter OT Err. UL(3sigma) (mid, days) (s) 2025-01-11 11:57:42 0.46301 51*70 R 21.20 0.15 21.4

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