GCN Circular 40828
Subject
GRB 250625A: SAO RAS possible optical afterglow
Event
Date
2025-06-25T21:47:40Z (2 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 250625A (The Fermi GBM team,
GCN 40824; Ferro et al., GCN 40825) with SAO RAS 1-m telescope
Zeiss-1000 equipped with CCD-photometer. We obtained 6 x 300 sec.
exposures in Rc band on June 25, 20:39:03--21:12:11 UT
(t_mid - T0 = 4.8447 hours).
Withtin the enhanced XRT error circle (Beardmore et al., GCN 40827)
we detect single object with the coordinates:
R.A. (J2000.0) = 17:26:02.1
Dec. (J2000.0) = +22:16:03.6 +/- 0".3
and brightness of R = 22.97 +/- 0.17, possible GRB OT.
Observations are ongoing to confirm variability of the object.
Preliminary photometry is based on the nearby USNO-B1.0
and has not corrected for the Galactic extinction.
R.A. Dec. (2000) R2
17:26:06.4 +22:16:29.4 14.75
17:26:03.7 +22:15:09.9 15.42
17:26:10.0 +22:13:56.8 15.03
17:26:01.4 +22:18:39.0 14.59