GCN 42977: GRB 251202A / EP251202a: Liverpool Telescope optical follow-up observations

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.