GCN Circular 40400
Subject
GRB 250507A: KAIT optical upper limit
Date
2025-05-08T18:37:31Z (3 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 SVOM GRB 250507A (Wang
et al., GCN 40374) starting at 06:37:30, May 07 UT, 165 seconds
after the burst. Observations were performed in 3 x 3 tiling mode,
and 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 (Maggi et al.,
GCN 40381; Zhang et al., GCN 40385; Osborne et al., GCN 40389),
neither in single image, nor in the co-add images. We estimate
the limiting magnitude of our coadd image to be ~20.0 mag at a
mid-time of 15.0 minutes after the burst, consistent with the
upper limit reported by other groups (Ducoin et al., GCN 40376;
Xin et al., GCN 40379; Brivio et al., GCN 40380)