TITLE:   GCN CIRCULAR
NUMBER:  31725
SUBJECT: GRB 220310A: MAXI/GSC detection
DATE:    22/03/10 01:24:33 GMT
FROM:    Motoko Serino at Aoyama Gakuin U.  <serino@phys.aoyama.ac.jp>

H. Negoro, M. Nakajima (Nihon U.), M. Serino (AGU), Y. Kawakubo (LSU),
K. Kobayashi, K. Asakura, K. Seino (Nihon U.),
T. Mihara, T. Tamagawa, J. Li, M. Matsuoka (RIKEN),
T. Sakamoto, S. Sugita, K. Komachi, H. Hiramatsu, A. Yoshida (AGU),
Y. Tsuboi, W. Iwakiri, H. Kawai, Y. Okamoto, S. Kitakoga, J. Kohara (Chuo U.),
M. Shidatsu, M. Iwasaki (Ehime U.),
N. Kawai, M. Niwano, R. Hosokawa, Y. Imai, N. Ito, Y. Takamatsu (Tokyo Tech),
S. Nakahira, S. Ueno, H. Tomida, M. Ishikawa, M. Tominaga, T. Nagatsuka, M. Kurihara (JAXA),
Y. Ueda, S. Yamada, S. Ogawa, K. Setoguchi, T. Yoshitake, Y. Goto, R. Uematsu, K. Inaba (Kyoto U.),
H. Tsunemi (Osaka U.),
M. Yamauchi, Y. Nonaka, T. Sato, R. Hatsuda, R. Fukuoka (Miyazaki U.), T. Kawamuro (UDP/NAOJ),
K. Yamaoka (Nagoya U.),
M. Sugizaki (NAOC) 
report on behalf of the MAXI team:
The MAXI/GSC nova alert system triggered on a bright uncatalogued X-ray 
transient source at 2022-03-10T00:27:57 UT.
Assuming that the source flux was constant over the transit,
we obtain the source position at
(R.A., Dec) = (168.612 deg, 23.451 deg) = (11 14 26, +23 27 03) (J2000)
with a 90% C.L. statistical error of 0.16 deg and an additional systematic 
uncertainty of 0.1 deg (90% containment radius).
Without assumptions on the source constancy, we obtain a rectangular error
box for the transient source with the following corners:
(168.038, 23.325) deg = (11 12 09, +23 19 29) (J2000)
(168.176, 23.093) deg = (11 12 42, +23 05 34) (J2000)
(169.335, 23.670) deg = (11 17 20, +23 40 12) (J2000)
(169.197, 23.903) deg = (11 16 47, +23 54 10) (J2000)
The X-ray flux averaged over the scan was 348 +- 37 mCrab
(4.0-10.0keV, 1 sigma error).
There was no significant excess flux in the previous transit at 3/9 22:55 UT
with an upper limit of 20 mCrab.