TITLE:   GCN CIRCULAR
NUMBER:  35646
SUBJECT: GRB 240128A: MAXI/GSC detection
DATE:    24/01/28 22:09:40 GMT
FROM:    Kazutaka Yamaoka at Nagoya Univ. <yamaoka@isee.nagoya-u.ac.jp>


K. Yamaoka (Nagoya U.), H. Negoro (Nihon U.), M. Serino (AGU),
W. Iwakiri (Chiba U.), M. Nakajima, K. Kobayashi, M. Tanaka, 
Y. Soejima, Y. Kudo (Nihon U.), T. Mihara, T. Kawamuro, S. Yamada, 
T. Tamagawa, N. Kawai, M. Matsuoka (RIKEN), T. Sakamoto, S. Sugita,
H. Hiramatsu, H. Nishikawa, A. Yoshida (AGU), Y. Tsuboi, S. Urabe, 
S. Nawa, N. Nemoto, E.Goto (Chuo U.), M. Shidatsu, Y. Niida (Ehime U.),
I. Takahashi, M. Niwano, S. Sato, N. Higuchi, Y. Yatsu (Tokyo Tech),
S. Nakahira, S. Ueno, H. Tomida, M. Ishikawa, S. Ogawa, T. Kurihara (JAXA),
Y. Ueda, K. Setoguchi, T. Yoshitake, Y. Nakatani, Y. Okada (Kyoto U.),
M. Yamauchi, Y. Hagiwara, Y. Umeki, Y. Otsuki (Miyazaki U.),
Y. Kawakubo (LSU), and M. Sugizaki (NAOC)


The MAXI/GSC nova alert system triggered on an uncatalogued X-ray
transient source at 15:14:03 UT on January 28, 2024.
Because our localization program did not run, we can not provide a
precise error region.
The source position determined with the nova alert system (Negoro et
al. 2016) is

(R.A., Dec) = (139.846 deg, -5.053 deg) = (09 19 23.04, -05 03 10.8) (J2000)

with an uncertainty of more than 30 arc-min. The burst duration is
about 30 sec, and the averaged X-ray flux in the 2-10 keV range was about 600 mCrab.
This event was also detected by INTEGRAL SPI-ACS. 
There was no significant excess flux in the previous transit at 13:37 UT
with an upper limit of 20 mCrab.