GCN Circular 39576
Subject
EP250302a: SAO RAS optical observations
Date
2025-03-03T16:32:59Z (6 days ago)
From
Moskvitin Alexander at SAO RAS <mosk@sao.ru>
Via
Web form
A. S. Moskvitin, O. A. Maslennikova (SAO RAS), A. Pozanenko (IKI)
and N. Pankov (HSE, IKI) report on behalf of larger collaboration.
We observed the field of the X-ray transient EP250302a (Dai et al.,
GCN 39556; Page et al., GCN 39557) with SAO RAS 1-m telescope
Zeiss-1000 equipped with CCD-photometer under mediocre weather
conditions. We obtained two sets of 300-sec images in Rc band.
1st set: 2025.03.02, 20:33:49 -- 2025.03.02, 22:09:49 UT
(t_mid - T0 = 0.24010 days = 5.7625 hours);
2nd set: 2025.03.02, 23:55:53 -- 2025.03.03, 01:00:10 UT,
(t_mid - T0 = 0.36942 days = 8.8660 hours).
The OT (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) is clearly detected
in our stacked frames with the following brightness.
Date UT start t-T0 (mid),d Exp.,s Filter OT Err. UL(3sigm)
2025.03.02 20:33:49 0.24010 8x300 R 20.18 0.09 22.5
2025.03.02 23:55:53 0.36942 7x300 R 20.51 0.10 22.5
Above photometry is preliminary and calibrated against R2 magnitudes
of nearby USNO-B1 stars and not corrected for the Galaxy extinction.