TITLE: GCN CIRCULAR NUMBER: 40065 SUBJECT: GRB 250403A: KAIT optical observations DATE: 25/04/04 18:53:09 GMT FROM: Weikang Zheng at UC Berkeley 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 250403A (Julakanti et al., GCN 40026; Fermi GBM team, GCN 40025) with a set of 120x60s images in the clear (roughly R) filters, at a mid time of 16.0 hours after the trigger. We marginally detected the optical afterglow (Starling et al., GCN 40028; Wu et al., GCN 40029; Du et al., GCN 40031; Li et al., GCN 40032, Julakanti et al., GCN 40034; Ghosh et al., GCN 40039; Jiang et al., GCN 40041; PĂ©rez-Fournon et al., GCN 40043; Brivio et al., GCN 40044; Xin et al., GCN Circ. 40045) in the coadd image with a brightness of 21.2 +/- 0.4 mag (Vega).