GCN Circular 42977
Subject
GRB 251202A / EP251202a: Liverpool Telescope optical follow-up observations
Event
Date
2025-12-03T20:41:04Z (a day ago)
From
A. Bochenek at Liverpool John Moores University <a.m.bochenek@2023.ljmu.ac.uk>
Via
Web form
A. Bochenek, D. A. Perley (LJMU) and A. Y. Q. Ho (Cornell) report:
We observed the field of GRB 251202A/EP251202a (Fermi GBM team, GCN 42933; Bala et al., GCN 42957; Zhang et al., GCN 42937; Liang et al., GCN 42946) using the IO:O optical camera on the 2m robotic Liverpool Telescope. We obtained two epochs, separated by ~30 minutes, of 6x120s exposures with the SDSS r filter starting at 2025-12-03 03:24: UT, approximately 25.8 hours after trigger.
We report detections in both epochs, at the position of the afterglow first reported by Li et al., GCN 42934:
MJD (mid) T_mid-T_0 Filter Mag. (AB)
61012.15590 25.89 h r 19.99 ± 0.05
61012.17610 26.38 h r 20.18 ± 0.09
The seeing was poor throughout the observations, with the second epoch being more affected. The photometry was calibrated using nearby PanSTARRS secondary standards and was not corrected for extinction.