GCN Circular 23034
Subject
GRB 180721A: KAIT Optical Upper Limit
Date
2018-07-25T00:13:00Z (6 years ago)
From
Weikang Zheng at UC Berkeley <weikang@berkeley.edu>
WeiKang Zheng 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 180721A (Sbarufatti et al.,
GCN 22994) starting at 11:25:23 UT, ~19 minutes after the burst.
Observations were performed with an automatic sequence in the
clear (roughly R), V, and I filters, and the exposure time was 20 s
per image. We do not detect any optical afterglow candidate within
the enhanced XRT position error circle (Goad et al., GCN 22997)
neither in single image, nor in the co-add images.
The typical limiting magnitude of our single clear image is about
19.5 mag calibrated to the Pan-STARRS1 catalog.