TITLE: GCN CIRCULAR NUMBER: 21688 SUBJECT: LIGO/Virgo G298936 : MAXI/GSC observations DATE: 17/08/25 12:10:11 GMT FROM: Satoshi Sugita at Tokyo Inst. of Tech. S. Sugita, N. Kawai (Tokyo Tech), M. Serino (RIKEN), H. Negoro (Nihon U.), S. Ueno, H. Tomida, M. Ishikawa, Y. Sugawara, N.Isobe, R. Shimomukai (JAXA), T. Mihara, M. Sugizaki, S. Nakahira, W. Iwakiri, M. Shidatsu, M. Matsuoka (RIKEN), T. Yoshii, Y. Tachibana, S. Harita, Y. Muraki, K. Morita (Tokyo Tech), A. Yoshida, T. Sakamoto, Y. Kawakubo, Y. Kitaoka, T. Hashimoto (AGU), H. Tsunemi, T. Yoneyama (Osaka U.), M. Nakajima, T. Kawase, A. Sakamaki (Nihon U.), Y. Ueda, T. Hori, A. Tanimoto, S. Oda (Kyoto U.), Y. Tsuboi, Y. Nakamura, R. Sasaki (Chuo U.), M. Yamauchi, C. Hanyu, K, Hidaka (Miyazaki U.), T. Kawamuro (NAOJ), K. Yamaoka (Nagoya U.) report on behalf of the MAXI team: We examined the MAXI/GSC all-sky X-ray images (2-20 keV) obtained in the orbit and the day after the LVC trigger G298936 at 2017-08-23 13:13:58.518 UTC (GCN 21656). GSC scanned more than 76% of the whole sky in the 92-min orbit, which includes 81.0% of the 90% region in the bayestar skymap scanned from the trigger time. One day image obtained between 8-23 13:13:58 and 08-24 12:49 UTC covers 100% of the 90% region in the bayestar skymap. No significant new source was found in these images and the 2-20 keV averaged photon counts in the skymap region is 0.26 counts/sec. The 1-sigma (3-sigma) averaged upper limits obtained from the one-scan and one-day images in the bayestar skymap are 12(36) and 2(6) mCrab, respectively (see Serino et al., 2017 for the upper limit calculation). If you require information of X-ray flux by MAXI/GSC at specific coordinates, please contact the submitter of this circular by email.