TITLE: GCN CIRCULAR NUMBER: 39586 SUBJECT: EP250302a: Mondy Continued Optical Observations DATE: 25/03/04 10:06:19 GMT FROM: Nicolai Pankov at HSE, IKI RAS colinsergesen@gmail.com
N. Pankov (HSE, IKI), A. Pozanenko (IKI), E. Klunko (ISTP), A. Moskvitin (SAO RAS) report on behalf of IKI-GRB-FuN:
We performed optical observations of the field of a fast X-Ray transient EP250302a (Dai et al., GCN 39556; Page et al., GCN 39557) in the R filter with the 1.5-meter telescope of Sayan Solar Observatory (Mondy). The observations began on 2025-03-03 (UT) 19:29:15, i.e. ~1.18 days since trigger. The optical source (Zhu et al., GCN 39550; Busmann et al., GCN 39551; Leonini et al., GCN 39553; Wu et al., GCN 39555; Xin et al., GCN 39558; Adami et al., GCN 39560; Yang et al., GCN 39561; Becerra et al., GCN 39562; Izzo et al., GCN 39564; Pankov et al., GCN 39565; Reguitti, GCN 39568; Komesh et al., GCN 39569; Shilling and Breeveld, GCN 39570; Aryan et al., GCN 39572; Moskvitin et. al, GCN 39576; Wu et. al, GCN 39578) is detected in the stacked image of 28*120 seconds. The preliminary photometry is as follows:
Date UT start t-T0 Exptime Filter OT Err. UL (mid, days) (s) (3sigma) 2025-03-03 19:29:15 1.18136 28*120 R 22.12 0.14 23.4
The photometry is based on nearby stars from the USNO-B1.0 catalog (R2 magnitudes) and has not been corrected for the Galactic extinction.
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