TITLE:   GCN CIRCULAR
NUMBER:  23368
SUBJECT: GRB 181023A: KAIT Optical Upper Limit
DATE:    18/10/23 04:24:34 GMT
FROM:    Weikang Zheng at UC Berkeley  <weikang@berkeley.edu>

Xuhui Han (NAOC), WeiKang Zheng (UC Berkeley) and Alexei V. Filippenko
(UC Berkeley) report on behalf of the KAIT GRB team:

The 0.76-m Katzman Automatic Imaging Telescope (KAIT), located at
Lick Observatory, responded to Swift GRB 181023A (Marshall et al.,
GCN 23366) starting at 02:16:07 UT, ~12 minutes after the burst
under dusk twilight condition. Observations were performed in the
clear (roughly R) filters, and the exposure time was 60s per image.
Observations lasted for about 25 minutes before it set beyond KAIT
hour agnle limit. We do not detect any optical afterglow candidate
within the XRT position error circle (Marshall et al., GCN 23366)
neither in single image, nor in the co-add images. The typical
limiting magnitude of our single clear image is about 19.0 mag
calibrated to the Pan-STARRS1 catalog.