TITLE: GCN CIRCULAR NUMBER: 18361 SUBJECT: LIGO/Virgo G184098: optical transient search with Kiso Schmidt telescope and KWFC on behalf of J-GEM collaboration DATE: 15/09/24 01:38:06 GMT FROM: Tomoki Morokuma at U.TokyoJ-GEM Tomoki Morokuma (The University of Tokyo), Masaomi Tanaka (National Astronomical Observatory of Japan), Michitoshi Yoshida, Koji S. Kawabata, Yousuke Utsumi (Hiroshima University), Mamoru Doi, Kentaro Motohara, Yoichi Tamura (The University of Tokyo), Fumio Abe (Nagoya University), Kenta Fujisawa (Yamaguchi University), Nobuyuki Kawai (Tokyo Tech), Koji Ohta (Kyoto University), and Kenshi Yanagisawa (National Astronomical Observatory of Japan) on behalf of J-GEM collaboration We report optical imaging follow-up observations for a part of the northern skymap regions of G184098 with 1.05-m Kiso Schmidt telescope and its 2.2 deg x 2.2 deg field-of-view camera, Kiso Wide Field Camera (KWFC; Sako et al. 2012, SPIE, 8446, 84466L). We took 180-sec exposure images in i-band for 5 fields as below (about 24 deg2 in total). RA(J2000) Dec(J2000) starting UTC 09:05:35.52 +10:27:00.0 2015-09-17 19:07:34 09:14:32.16 +10:27:00.0 2015-09-17 19:13:09 09:23:28.80 +10:27:00.0 2015-09-17 19:18:31 09:32:25.44 +10:27:00.0 2015-09-17 19:23:54 09:41:22.08 +10:27:00.0 2015-09-17 19:36:01 The 5-sigma limiting magnitudes (AB) are 18.8 mag and 16.2 mag in the first four exposures and the last exposure, respectively. The data reduction and transient finding with image subtraction were performed with the pipeline developed for Kiso Supernova Survey (KISS) as described in Morokuma et al. (2014, PASJ, 66, 114). The SDSS i-band data was used as reference images for the subtraction. We do not find any transients which are likely associated with external galaxies.