GCN Circular 41805
Subject
EP250911a: SAO RAS optical observations
Event
Date
2025-09-11T23:47:13Z (8 hours ago)
From
Alexander Moskvitin at SAO RAS <mosk@sao.ru>
Via
Web form
A. Moskvitin, O. Spiridonova (SAO RAS)
report on behalf of GRB follow-up collaboration.
We observed the field of EP250911a (Liang et al., GCN 41788,
Evans et al., GCN 41802) with the 1-m SAO RAS telescope
Zeiss-1000 equipped with CCD-photometer. We obtained 9 x 300 sec.
images in Rc band on September 11, 21:38:05--22:34:14 UT
(t_mid - T0 = 13.12819 hours = 0.547008 days).
The OT (Quirola-Vasquez et al., GCN 41790, Angulo et al., GCN 41793;
Lai et al., GCN 41801) is clearly detected in the stacked image
with the brightness of R = 21.90 +/- 0.11 (R_lim = 23.0 mag).
This preliminary photometry is based on nearby SDSS stars
(magnitudes were converted with the Lupton 2005 equations)
and not corrected for Galactic extinction.