GCN Circular 42230
Subject
GRB 251013C: SAO RAS optical observations
Event
Date
2025-10-13T21:31:40Z (3 days ago)
From
Alexander Moskvitin at SAO RAS <mosk@sao.ru>
Via
Web form
A. S. Moskvitin, O. I. Spiridonova, V. V. Vlasyuk (SAO RAS),
N. Pankov (HSE, IKI), A. Pozanenko (IKI), A. Ghosh, S. Razzaque
(CAPP, University of Johannesburg), Tao An and Yuanqi Liu
(Shanghai Astronomical Observatory) report on behalf of GRB follow-up
collaboration and IKI-GRB-FuN.
We observed the field of the GRB 251013C (The Fermi GBM team,
GCN 42221; Rakotondrainibe et al., GCN 42222) with the 1-m SAO RAS
telescope Zeiss-1000 equipped with the CCD-photometer.
The observations started on 2025.10.13T19:47:54 UT
(t_mid - T0 = 2.1369 hours).
The OT (Palmerio et al., GCN 42223; Perez-Garcia et al., GCN 42225;
Konno et al., GCN 42226; Martin-Carrillo et al., GCN 42227; Masi,
GCN 42228; Palmerio et al, GCN 42229) is clearly detected
in the individual images with the following brightness.
Date UT start t-T0 Exp. Filter OT Err.
(mid, d) (s)
2025.10.13 19:47:54 0.03631 300 Rc 15.84 +/- 0.01
2025.10.13 20:04:02 0.04033 100 Rc 16.05 +/- 0.01
2025.10.13 20:15:34 0.04353 100 Rc 16.21 +/- 0.01
Preliminary photometry is based on the nearby SDSS objects
(magnitudes converted with Lupton 2005 equations)
and has not corrected for the Galactic extinction.
The observations with the 1-m telescope in BVRI filters
and also with the 0.5-m telescope AS-500/2 are ongoing.