[vsnet-grb-info 28400] GRB 210725A: KAIT Optical Upper Limit

[GCN Circulars]

TITLE:   GCN CIRCULAR
NUMBER:  30503
SUBJECT: GRB 210725A: KAIT Optical Upper Limit
DATE:    21/07/25 05:20:35 GMT
FROM:    Weikang Zheng at UC Berkeley  <weikang at 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 210725A (Bernardini et al.,
GCN 30501) starting at 56 minutes after the burst. A total of
30x60s images were obtained in the clear (roughly R) filters.
We do not detect any optical afterglow candidate within the XRT
position error circle (Bernardini et al., GCN 30501), neither in
single image, nor in the co-add images. The typical limiting magnitude
of our single clear image is about 18.5 mag calibrated to the PS1 catalog.