TITLE:   GCN CIRCULAR
NUMBER:  41665
SUBJECT: GRB 250831A (SVOM trigger sb25083102): KAIT confirmation of stellar flare
DATE:    25/09/03 04:11:08 GMT
FROM:    Weikang Zheng at UC Berkeley <weikang@berkeley.edu>

WeiKang Zheng (UCB), Xuhui Han (NAOC), Pinpin Zhang (NAOC) and

Alexei V. Filippenko (UCB) report on behalf of the KAIT GRB team:


The 0.76-m Katzman Automatic Imaging Telescope (KAIT), located at

Lick Observatory, observed the field of GRB 250831A (SVOM trigger

sb25083102; Xie et al., GCN 41614) starting at 09:32:33, 180 seconds

after the burst. Observations were performed in 3 x 3 tiling mode,

and a set of clear (roughly R) filter images were obtained. The first

image covered the proposed flare star G 272-61 (Wu et al., GCN 41615;

Magnani et al., GCN 41616; Xie et al., GCN 41618; Li et al., GCN

41654) was at 09:36:55, 442 seconds after the burst. Although the

star was saturated in KAIT images, photometry with a large aperture

clearly shows the magnitude decreased from 9.2 mag to 10.2 mag (faded

by 1.0 mag) about 2 hours later. This is similar to the light curve

reported by SVOM/VT, confirming this event is due to a stellar flare.