TITLE:   GCN CIRCULAR
NUMBER:  21646
SUBJECT: LIGO/Virgo G298389 : MAXI/GSC observations
DATE:    17/08/22 17:01:32 GMT
FROM:    Satoshi Sugita at Tokyo Inst. of Tech.  <sugita@hp.phys.titech.ac.jp>

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
G298389 at 2017-08-19 15:50:46.990 UTC (GCN 21600).

GSC scanned more than 82% of the whole sky in the 92-min orbit,
which includes 76.3% of the 90% region in the LIB skymap
scanned from 16:29:17 to 16:47:45 UTC (T0+2310 to 3418 sec).
One day image obtained between 08-19 16:29:17 and 08-20 15:46:30 UTC
covers 86% of the 90% region in the LIB skymap.
No significant new source was found in these images
and the 2-20 keV averaged photon counts in the skymap region is 0.46 counts/sec.
The 1-sigma (3-sigma) averaged upper limits
obtained from the one-scan and one-day images in the LIB skymap are
11(33) and 3(9) 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.