GCN Circular 42917
Subject
EP251130a: KAIT optical observations
Event
Date
2025-12-01T09:16:17Z (19 hours ago)
From
Weikang Zheng at UC Berkeley <weikang@berkeley.edu>
Via
email
WeiKang Zheng (UCB), Xuhui Han (NAOC), Pinpin Zhang (NAOC) and
Alexei V. Filippenko (UCB) report on behalf of the KAIT GRB team:
The 0.76-m Katzman Automatic Imaging Telescope (KAIT), located at
Lick Observatory, automatically responded to EP251130a (Wu et al.,
GCN 42903) starting at 11:21:40 UT, 831 seconds after the burst.
A set of 10x20s, 10x40s, 60x60s clear (roughly R) filter images
were obtained. We clearly detected the optical afterglow (Dornic
et al., GCN 42904, He et al., GCN 42914; Gupta et al., GCN 42916)
in our coadd image. We measure its brightness decreased from 19.6
+/- 0.1 mag (Vega; mid time 16.45 min) to 20.2 +/- 0.2 mag (mid
time of 91.03 min) with a decay index of 0.46.
Additional 30x60s clear filter images were obtained the following
night at a mid time of 0.89 days after the burst. The OT is still
detected at 19.7 +/- 0.1 mag, indicating the OT has brightened.
More follow-up observations are encouraged.