M. Serino, T. Sakamoto (AGU), W. Iwakiri (Chuo U.), H. Negoro (Nihon U.), Y. Kawakubo (LSU),
N. Kawai, M. Niwano, R. Hosokawa, Y. Imai, N. Ito, Y. Takamatsu (Tokyo Tech),
M. Nakajima, K. Kobayashi, M. Tanaka, Y. Soejima (Nihon U.),
T. Mihara, T. Kawamuro, S. Yamada, T. Tamagawa, M. Matsuoka (RIKEN),
S. Sugita, H. Hiramatsu, A. Yoshida (AGU),
Y. Tsuboi, J. Kohara (Chuo U.),
M. Shidatsu, M. Iwasaki (Ehime U.),
S. Nakahira, S. Ueno, H. Tomida, M. Ishikawa, M. Tominaga, T. Nagatsuka, T. Kurihara (JAXA),
Y. Ueda, S. Ogawa, K. Setoguchi, T. Yoshitake, K. Inaba (Kyoto U.),
H. Tsunemi (Osaka U.),
M. Yamauchi, T. Sato, R. Hatsuda, R. Fukuoka, Y. hagiwara, Y. Umeki (Miyazaki U.),
K. Yamaoka (Nagoya U.),
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 17:33:25 UT on 2022 July 6 at
(R.A., Dec) = (0.219 deg, -16.471 deg) (J2000)
This position was consistent with GRB 220607A (GCN #32329) and the scan transit
was 5051 sec after the BAT trigger time (T0).
The scan was not completed because the GSC HV turned off due to the high
latitude constraint. The preliminary observed flux was about 200 mCrab in
the 2 - 10 keV band.
The transient was also observed at the next scan transit (17:53, T0+6260s) and
the flux decayed to about 60 mCrab in the same energy band.
We note that Swift/XRT also detected bright X-ray flare around T0+5400s.
There was no significant excess flux in the previous transit at 16:00 UT
and in the third transit at 19:26 UT with an upper limit of 20 mCrab for each.
Since the X-ray flaring activity of this GRB was unusual, we encourage