GCN Circular 34723

H. Negoro, M. Nakajima (Nihon U.),
T. Mihara, N. Kawai (RIKEN),
S. Sugita, M. Serino, H. Hiramatsu, H. Nishikawa, Y. Kondo (AGU),
Y. Kawakubo (LSU)
report on behalf of the MAXI team:

We examined MAXI/GSC all-sky X-ray images (2-20 keV)
after compact binary merger candidate S230917af at 2023-09-17 10:04:17 UTC .

At the trigger time of S230917af, the high-voltage of MAXI/GSC was on,
but the FOV was out of the 90% credible region of the cwb skymap.
The first one-orbit (92 min) scan observation with GSC after the event covered 100%
of the 90% credible region of the cwb skymap from 10:41:56 to 10:53:01 UTC (T0+2259 to T0+2924 sec).

There was a low significance burst-like X-ray event at 
(R.A., Dec) = (333.784 deg, 39.435 deg) = (22 15 08, +39 26 06) (J2000) 
with a statistical 90% C.L. error region of ~0.6 deg.
There is an additional systematic uncertainty of 0.1 deg (90% containment radius).
The sources region  was observed around 10:50:13 UTC.
The X-ray flux averaged over the scan was 48 +- 13 mCrab
(4.0-10.0keV, 1 sigma error).

If you require information about X-ray flux by MAXI/GSC at specific coordinates,
please contact the submitter of this circular by email.