TITLE:   GCN CIRCULAR
NUMBER:  29576
SUBJECT: GRB 210226A: KAIT Optical Upper Limit
DATE:    21/02/26 18:29:47 GMT
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 210226A (Beardmore et al.,

GCN 29568) starting at 04:56:15 UT, 738s after the burst.

Observations were performed with an automatic sequence in the

clear (roughly R), V, and I filters, and the exposure time was 20s

per image. We do not detect any optical afterglow candidate within

the enhanced XRT position error circle (Goad et al., GCN 29571),

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 USNOB1.0 catalog. Our result is consistent with

the optical upper limit reported by other groups (Jelinek et al.,

GCN 29570; Romanov, GCN 29572; Lipunov et al., GCN 29574).