MAXI/GSC detection of X-ray brightening from V4641 Sgr
ATel #14968; H. Negoro, M. Nakajima (Nihon U.), T. Mihara (RIKEN), K. Kobayashi, K. Asakura, K. Seino (Nihon U.), T. Tamagawa, M. Matsuoka (RIKEN), T. Sakamoto, M. Serino, S. Sugita, K. Komachi, A. Yoshida (AGU), Y. Tsuboi, W. Iwakiri, H. Kawai, Y. Okamoto, S. Kitakoga (Chuo U.), M. Shidatsu (Ehime U.), N. Kawai, M. Niwano, R. Hosokawa (Tokyo Tech), S. Nakahira, S. Ueno, H. Tomida, M. Ishikawa, M. Tominaga, T. Nagatsuka, T. Kurihara (JAXA), Y. Ueda, S. Yamada, S. Ogawa, K. Setoguchi, T. Yoshitake, Y. Goto, R. Uematsu (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.), Y. Kawakubo (LSU), and M. Sugizaki (NAOC)
on 13 Oct 2021; 12:24 UT
Credential Certification: Hitoshi Negoro (negoro@phys.cst.nihon-u.ac.jp)
Subjects: Black Hole, Transient
The MAXI/GSC nova alert system triggered on X-ray brightening from the black hole binary V4641 Sgr on October 4, 8, and 12, 2021.
The brightening has started around MJD 59430 (August 4, 2021). The 2-10 keV X-ray flux has been gradually increasing, and reached about 20 mCrab on October 12.
This is the 7th detection of the outbursts from V4641 Sgr with MAXI/GSC since 2009. The last outburst was observed from January to February in 2020 (MJD 58853-58970) with a peak flux of about 60 mCrab in the 2-10 keV band (also see ATel #13431, #13437, #13443, #13471, #13547).
Followup observations are encouraged.
V4641 Sgr of MAXI GSC data
