GCN Circular 38808
Subject
GRB 250103A: NOT optical observations
Date
2025-01-03T23:14:19Z (5 days ago)
From
Daniele B. Malesani at IMAPP / Radboud University <d.malesani@astro.ru.nl>
Via
Web form
D. Xu (NAOC), Z. P. Zhu (NAOC), D. B. Malesani (DAWN/NBI and Radboud Univ.), L. Izzo (INAF/OACn), A. de Ugarte Postigo (CNRS, OCA and LAM), A. Saccardi (CEA/Irfu), K. Valeckas (NBI), report on behalf of a larger collaboration:
We observed the optical counterpart (Li et al., GCN 38795; Qiu et al., GCN 38802) of the SVOM GRB 250103A (Wang et al., GCN 38786, 38787), using the Nordic Optical Telescope (NOT) equipped with the ALFOSC camera. Two observations by 200 s each were secured in the i band, with a mean time 2025 Jan 3.90 UT (8.16 hr after the GRB).
The optical counterpart is well detected, with an AB magnitude i = 21.14 +- 0.04, calibrated against nearby objects from the Pan-STARRS catalog.
We note that a relatively bright object (i ~ 22.8) is detected in the Legacy survey directly underlying the position of the optical afterglow.