TITLE:   GCN CIRCULAR
NUMBER:  41623
SUBJECT: LIGO/Virgo/KAGRA S250831cc: Coverage and upper limits from MAXI/GSC observations
DATE:    25/09/01 03:03:21 GMT
FROM:    Hitoshi Negoro at Nihon University/MAXI team <negoro.hitoshi@nihon-u.ac.jp>

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

We examined MAXI/GSC all-sky X-ray images (2-20 keV)
after compact binary merger candidate S250831cc at 2025-08-31 12:30:48.228 UTC.

At the trigger time of S250831cc, the high-voltage of MAXI/GSC was on,
but the FOV was out of the 90% credible region of the bayestar skymap.
The first one-orbit (92 min) scan observation with GSC after the event covered 48%
of the 90% credible region of the bayestar skymap from 13:12:46 to 13:24:01 UTC
 (T0+2518 to T0+3193 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.