| Circular_text |
TITLE: GCN CIRCULAR
NUMBER: 32882
SUBJECT: GRB 221028B: MAXI/GSC detection
DATE: 22/10/29 00:31:06 GMT
FROM: Motoko Serino at Aoyama Gakuin U.
H. Negoro (Nihon U.), M. Serino (AGU), M. Shidatsu (Ehime U.),
M. Nakajima, K. Kobayashi, M. Tanaka, Y. Soejima (Nihon U.),
T. Mihara, T. Kawamuro, S. Yamada, T. Tamagawa, M. Matsuoka (RIKEN),
T. Sakamoto, S. Sugita, H. Hiramatsu, H. Nishikawa, A. Yoshida (AGU),
Y. Tsuboi, W. Iwakiri, J. Kohara, S. Urabe, S. Nawa, N. Nemoto (Chuo U.),
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, T. Kurihara (JAXA),
Y. Ueda, S. Ogawa, K. Setoguchi, T. Yoshitake, K. Inaba (Kyoto U.),
M. Yamauchi, T. Sato, R. Hatsuda, R. Fukuoka, Y. Hagiwara, Y. Umeki (Miyazaki U.),
K. Yamaoka (Nagoya U.),
Y. Kawakubo (LSU),
M. Sugizaki (NAOC)
report on behalf of the MAXI team:
The MAXI/GSC nova alert system triggered a bright uncatalogued X-ray transient source
at 2022-10-28T20:57:52 UT.
Assuming that the source flux was constant over the transit,
we obtain the source position at
(R.A., Dec) = (215.098 deg, -36.880 deg) = (14 20 23, -36 52 48) (J2000)
with a 90% C.L. statistical error of 0.23 deg and an additional systematic
uncertainty of 0.1 deg (90% containment radius).
The X-ray flux averaged over the scan was 159 +- 26 mCrab
(4.0-10.0keV, 1 sigma error).
Without assumptions on the source constancy, we obtain a rectangular error
box for the transient source with the following corners:
(214.489, -35.809) deg = (14 17 57, -35 48 32) (J2000)
(214.045, -36.075) deg = (14 16 10, -36 04 30) (J2000)
(215.717, -37.852) deg = (14 22 52, -37 51 07) (J2000)
(216.165, -37.579) deg = (14 24 39, -37 34 44) (J2000)
There was no significant excess flux in the previous transit at 19:24 UT
and in the next transit at 22:09 UT with an upper limit of 20 mCrab for each.
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