GCN Circular 40963
Subject
EP250704a / GRB 250704B: SAO RAS optical observations
Event
Date
2025-07-05T01:03:17Z (23 days ago)
From
Alexander Moskvitin at SAO RAS <mosk@sao.ru>
Via
Web form
A. Moskvitin, O. Spiridonova (SAO RAS),
report on behalf of a GRB follow-up collaboration.
We observed the field of the GRB 250704B (Wang et al., GCN 40940),
EP250704a (Li et al., GCN 40941) with SAO RAS 1-m telescope
Zeiss-1000 equipped with CCD-photometer. We obtained 6 x 300 sec.
exposures in Rc band on July 4, 22:55:08--23:38:07 UT
(t_mid - T0 = 15.00 hours).
The OT (Schneider et al., GCN 40942; Malesani et al., GCN 40945;
Brivio et al., GCN 40947; Perez-Garcia et al., GCN 40957;
Gillanders et al., GCN 40958; Xin et al., GCN 40960;
Mohan et al., GCN 40962) is clearly detected in our stacked image
with the brightness of R = 20.80 +/- 0.18.
Preliminary photometry is based on the nearby USNO-B1.0 stars
and has not corrected for the Galactic extinction.