TITLE: GCN CIRCULAR NUMBER: 24625 SUBJECT: IGO/Virgo S190521g: Coverage and upper limits from MAXI/GSC observations DATE: 19/05/21 06:15:49 GMT FROM: Hitoshi Negoro at Nihon U H. Negoro (Nihon U.), N. Kawai, M. Sugizaki (Tokyo Tech), S. Sugita, M. Serino (AGU), M. Nakajima, W. Maruyama, M. Aoki, K. Kobayashi (Nihon U.), S. Nakahira, 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. Ueno, H. Tomida, M. Ishikawa, Y. Sugawara, 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.), Y. Kawakubo (LSU) report on behalf of the MAXI team: We examined MAXI/GSC all-sky X-ray images (2-20 keV) after the LVC trigger S190521g at 2019-05-21 03:02:29.447 UTC (GCN 24621). At the trigger time of S190521g, the high-voltage of MAXI/GSC was off, and it was turned on at T0+708 sec (+11.8 min). The first one-orbit (92 min) scan observation with GSC after the event covered 100% of the 90% credible region of the bayestar skymap from 03:14:17 to 04:21:47 UTC (T0+708 to T0+4758 sec). 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.