[vsnet-grb-info 23718] LIGO/Virgo S190923y: Coverage and upper limits from MAXI/GSC observations

[GCN Circulars]

TITLE:   GCN CIRCULAR
NUMBER:  25817
SUBJECT: LIGO/Virgo S190923y: Coverage and upper limits from MAXI/GSC observations  
DATE:    19/09/23 14:55:00 GMT
FROM:    Hitoshi Negoro at Nihon U  <negoro.hitoshi at nihon-u.ac.jp>

H. Negoro (Nihon U.), S. Sugita, M. Serino (AGU), N. Kawai (Tokyo Tech), 
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.), Y. Kawakubo (LSU), M. Sugizaki (NAOC) 
report on behalf of the MAXI team: 

We examined MAXI/GSC all-sky X-ray images (2-20 keV) 
after the LVC trigger S190923y at 2019-09-23 12:55:59.645 UTC (GCN 25814). 

At the trigger time of S190923y, the high-voltage of MAXI/GSC was on. 
The instantaneous field of view of GSC at the GW trigger time covered 3% 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 90% 
of the 90% credible region of the bayestar skymap from 12:55:59 to 14:27:58 UTC (T0+0 to T0+5519 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.