MAXI/GSC detection of a new hard X-ray transient Swift J1727.8-1613 (GRB 230824A)
ATel #16205; H. Negoro (Nihon U.), M. Serino (AGU), 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 (Chuo U.), M. Shidatsu (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 (Kyoto U.), M. Yamauchi, Y. Hagiwara, Y. Umeki, Y. Otsuki (Miyazaki U.), K. Yamaoka (Nagoya U.), Y. Kawakubo (LSU), M. Sugizaki (NAOC), and W. Iwakiri (Chiba U.)
on 25 Aug 2023; 00:29 UT
Credential Certification: Hitoshi Negoro (negoro@phys.cst.nihon-u.ac.jp)
Subjects: X-ray, Transient
Referred to by ATel #: 16206, 16207, 16209, 16210, 16211, 16215, 16216, 16217, 16219, 16225, 16230, 16231, 16232, 16235, 16237, 16238, 16242, 16243, 16245, 16247, 16273, 16276, 16279, 16287, 16295, 16490, 16541, 16552
The MAXI/GSC has detected the hard X-ray transient Swift J1727.8-1613 (GRB 230824A: GCN #34536, #34537) since the scan transit at 10:20 on 2023 August 24. The source flux is increasing rapidly, reaching more than 2 Crab at 10-20 keV at 21:10 and 22:44, which supports the possibility that the source is a Galactic transient, not a GRB (GCN #23540).
The hard and rapid variations suggests that the source is a V404 Cyg like object. Followup observations are highly encouraged.