TITLE:   GCN CIRCULAR
NUMBER:  37127
SUBJECT: GRB 240809A: KAIT optical observations
DATE:    24/08/10 06:19:23 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 GRB 240809A detected by Swift

(Evans et al., GCN 37110) starting about 0.86 days after the bust.

Observations were performed in the clear (roughly R) filter, and

the exposure time was 60s per image. A total of 30 images were

obtained. We detected the optical afterglow (Evans et al.,

GCN 37110; Dubay et al., GCN 37114; Jiang et al., GCN 37116;

Gottumukkala et al., GCN 37122; Mohan et al., GCN 37125) in our

coadd image in clear band. We measured its brightness of 21.0 +/-

0.2 mag at a mid time of ~0.86 days after the burst, calibrated to

the Pan-STARRS1 catalog.