TITLE: GCN CIRCULAR NUMBER: 25300 SUBJECT: LIGO/Virgo S190808ae: Coverage and upper limits from MAXI/GSC observations DATE: 19/08/09 01:30:16 GMT FROM: Motoko Serino at RIKEN/MAXI M. Serino, S. Sugita (AGU), H. Negoro (Nihon U.), N. Kawai, M. Sugizaki (Tokyo Tech), Y. Kawakubo (LSU), M. Nakajima, W. Maruyama, M. Aoki, K. Kobayashi (Nihon U.), T. Mihara, T. Tamagawa, M. Matsuoka (RIKEN), T. Sakamoto, H. Nishida, A. Yoshida (AGU), Y. Tsuboi, W. Iwakiri, R. Sasaki, H. Kawai, T. Sato (Chuo U.), M. Shidatsu (Ehime U.), M. Oeda, K. Shiraishi (Tokyo Tech), S. Nakahira, Y. Sugawara, S. Ueno, H. Tomida, M. Ishikawa, N. Isobe, R. Shimomukai, M. Tominaga (JAXA), Y. Ueda, A. Tanimoto, S. Yamada, S. Ogawa, K. Setoguchi, T. Yoshitake (Kyoto U.), H. Tsunemi, T. Yoneyama, K. Asakura, S. Ide (Osaka U.), M. Yamauchi, S. Iwahori, Y. Kurihara, K. Kurogi, K. Miike (Miyazaki U.), T. Kawamuro (NAOJ), K. Yamaoka (Nagoya U.) report on behalf of the MAXI team: We examined MAXI/GSC all-sky X-ray images (2-20 keV) after the LVC trigger S190808ae at 2019-08-08 22:21:21.496 UTC (GCN #25296). At the trigger time of S190808ae, the high-voltage of MAXI/GSC was on. The instantaneous field of view of GSC at the GW trigger time covered 0.4% of the 90% credible region of the bayestar sky map, in which we found no significant new X-ray source. The first one-orbit (92 min) scan observation with GSC after the event covered 98% of the 90% credible region of the bayestar skymap from 22:21:21 to 23:53:18 UTC (T0+0 to T0+5517 sec). The position of IceCube neutrino event (GCN #25297) was not observed during the orbit. No significant new source was found in the region in the one-orbit scan observation. A typical 1-sigma averaged upper limit obtained in one scan observation is 20 mCrab at 2-20 keV. If you require information about X-ray flux by MAXI/GSC at specific coordinates, please contact the submitter of this circular by email.