TITLE:   GCN CIRCULAR
NUMBER:  24635
SUBJECT: LIGO/Virgo S190521r: Coverage and upper limits from MAXI/GSC observations
DATE:    19/05/21 09:35:58 GMT
FROM:    Motoko Serino at RIKEN/MAXI  <motoko@crab.riken.jp>

M. Serino, S. Sugita (AGU),
N. Kawai, M. Sugizaki (Tokyo Tech), H. Negoro (Nihon U.), 
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 S190521r at 2019-05-21 07:43:59.463 UTC (GCN 24632).

At the trigger time of S190521r, the high-voltage of MAXI/GSC was off,
and it was turned on at T0+848 sec (+14.1 min).
The first one-orbit (92 min) scan observation with GSC after the event covered 99% 
of the 90% credible region of the bayestar skymap from 07:58:17 to 09:09:32 UTC (T0+858 to T0+5133 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.