GCN Circular 41686
Subject
GRB 250903A: LCO optical observation
Event
Date
2025-09-04T01:48:35Z (a month ago)
From
SVOM_group <svomgroup@bao.ac.cn>
Via
Web form
A. Saccardi (CEA/Irfu), L. P. Xin (NAOC), C. Wu (NAOC), B. Cordier (CEA/Irfu), report on behalf of the SVOM mission team:
We observed the field of the GRB 250903A detected by SVOM/ECLAIRs (Maiolino et al., GCN 41677) with the LCO 1m telescope at South African Astronomical Observatory equipped with the Sinistro instrument.
Our observation started on 2025-09-03 at 23:25:00 UT (6.0 hr after the trigger) and we obtained 4x300 s exposures using the SDSS r filter. In the stacked image, we detected the optical afterglow (An et al., GCN 41679, Xin et al., GCN 41684, Pérez-Fournon et al. GCN 41685) within the errorbox of SVOM/MXT (Gotz et al., GCN 41681).
We derived the following magnitude r = 20.04 +/- 0.11 mag calibrated by the Guide Star Catalog, Version 2.3.2 (GSC2.3) (STScI, 2006) and not corrected for Galactic extinction.
This project is funded by the SVOM collaboration.