XRISM/Xtend Transient Search (XTS) detected an X-ray brightening from XRISM J1729-1410
ATel #18092; K. Hasegawa (Kyoto U.), T. Takagi (Ehime U.), T. Hakamata, Y. Kanemaru, A. Miyamoto, Y. Omiya, Y. Uchida, T. Yoneyama (JAXA), M. Audard (U. de Geneve), E. Behar (Technion), K. Fukushima (TUS), H. Iinuma (Tohoku U.), S. Inoue (Kyoto U.), Y. Ishihara (Chuo U.), N. Ishii (Kyoto U.), S. Ishiwata (Chuo U.), C. Kang (Ehime U.), R. Kawada (Kyoto U.), M. Kikuchi (Ehime U.), T. Kiyomoto (Saitama U.), T. Kohmura (TUS), H. Kuramoto (UOsaka), W. Lee (Kyoto U.), Y. Maeda (JAXA), H. Matsumoto (UOsaka), A. Miyamoto (UOsaka), M. Mizumoto (UTEF), Y. Motogami (Saitama U.), H. Murakami (TGU), T. Narita (RIKEN), M. Nobukawa (NUE), H. Noda (Tohoku U.), S. Ogawa (TUS), K. Sakamoto (Kyoto U.), Y. Sakamoto (Tohoku U.), M. Shidatsu (Ehime U.), H. Takahashi (Hiroshima U.), S. Takatsuka (UOsaka), F. Takisawa (Ehime U.), Y. Terada (Saitama U., JAXA), Y. Terashima (Ehime U.), Y. Tsuboi (Chuo U.), A. Uchida, H. Uchida (JAXA), T. Usuki (Ehime U.), A. Yoshimoto (NWU), M. Yoshimoto (Ehime U.)
on 6 Oct 2026; 11:51 UT
Credential Certification: Megumi Shidatsu (shidatsu.megumi.wr@ehime-u.ac.jp)
Subjects: X-ray, Transient
XRISM/Xtend Transient Search (XTS) detected an X-ray brightening from an X-ray source XRISM J1729-1410 on 2026-10-03 TT.
The source position was determined to be (R.A., Dec.) = (262.249, -14.159), with a systematic error of ∼ 40 arcsec.
A plausible counterpart is an X-ray source 4XMM J172859.4-140929 located ∼ 8 arcsec apart from the position of XRISM J1729-1410, respectively.
The brightening started at ∼ 05:10 TT on 2026-10-03 and continued until the end of the observation at ∼ 11:01 TT on 2026-10-03.
The time-averaged spectrum over the entire observation is reproduced with an absorbed power-law model, with an absorption of NH < 4 × 1021cm-2 and a photon index of Γ ∼ 1.6.
The flux is estimated to be ∼ 6 × 10-13 erg s-1 cm-2 (0.4 – 10.0 keV).
A systematic error of roughly 20% should be considered for the estimated flux.
