TITLE: GCN CIRCULAR NUMBER: 23572 SUBJECT: GRB 181225A: KAIT Follow-Up Observations with Upper Limit DATE: 18/12/28 04:44:24 GMT FROM: Weikang Zheng at UC Berkeley WeiKang Zheng, Keto Zhang, Alexei V. Filippenko, and Sergiy Vasylyev (UC Berkeley) 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 the AGILE-, GBM- and LAT-detected burst GRB 181225A (Ursi et al., GCN Circ. 23560; Arimoto et al. GCN Circ., 23561; Poolakkil et al., GCN Circ. 23562). More than 250 galaxies near the Fermi/LAT localization (Arimoto et al. GCN Circ., 23561) were selected from the Glade catalog (http://aquarius.elte.hu/glade/) according to their priority score. On 2018 Dec. 26 UT, KAIT observed 82 of them having top-priority scores, with each clear-filter exposure time being 60 s. The first image was taken at 01:47:23 UT, about 14.05 hr after AGILE/MCAL trigger time, and the last image at 04:24:11 UT. For the two Swfit/XRT sources reported by D'Elia (GCN 23565), the first one was not covered by KAIT images. The second source, which was considered to be a candidate X-ray afterglow for GRB181225A, was covered by one of the KAIT image taken at 03:46:38 UT (namely 16.04 hours after AGILE/MCAL trigger. However, we do not detect any optical afterglow candidate around the second XRT source, with limiting mag ~19.0 calibrated to the Pan-STARRS1 catalog.