GCN Circular 40401
Subject
EP250508a: KAIT optical upper limit
Date
2025-05-08T18:38:55Z (2 days 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, observed the field of EP250508a (Liang et al.,
GCN 40390) starting at 06:17, May 08 UT, about 14 minutes after
the burst. A set of clear (roughly R) filter images were obtained.
Preliminary analysis do not reveal any new optical counterpart
candidate within the X-ray afterglow error circles (Liang et al.,
GCN 40390; Zhao et al., GCN 40399). Due to the bright moonlight,
our image quality are degraded and we estimate the limiting
magnitude of our single image to be ~17.0 mag, shallower than the
upper limit reported by other groups (Ugarte Postigo et al., GCN
40391; Lipunov et al., GCN 40393; Brivio et al., GCN 40395).