XRISM/Xtend Transient Search (XTS) detected an X-ray flare from Pul -3 540245
ATel #17453; S. Takatuska (UOsaka), H. Matsumoto (UOsaka), K. Fukushima, Y. Kanemaru, S. Ogawa, Y. Uchida, T. Yoneyama (JAXA), M. Audard (U. de Geneve), E. Behar (Technion), T. Hakamata (UOsaka), S. Inoue (Kyoto U.), Y. Ishihara (Chuo U.), C. Kang (Ehime U.), T. Kiyomoto (Saitama U.), T. Kohmura (TUS), H. Kuramoto (UOsaka), J. Kurashima (U. of Miyazaki), Y. Maeda (JAXA), T. Matsushima (U. of Miyazaki), A. Miyamoto (UOsaka), M. Mizumoto (UTEF), K. Mori (U. of Miyazaki), Y. Motogami (Saitama U.), N. Nagashima (Chuo U.), T. Narita (Kyoto U.), M. Nobukawa (NUE), H. Noda (Tohoku U.), Y. Sakamoto (Tohoku U.), M. Shidatsu (Ehime U.), H. Sugai (Chuo U.), H. Takahashi (Hiroshima U.), T. Takagi (Ehime U.), R. Takemoto (U. of Miyazaki), Y. Terada (Saitama U., JAXA), Y. Terashima (Ehime U.), Y. Tsuboi (Chuo U.), H. Uchida (Kyoto U.), M. Yoshimoto (Ehime U.), S. Ueda (Kanazawa U.)
on 25 Oct 2025; 03:32 UT
Credential Certification: Hironori Matsumoto (matumoto@ess.sci.osaka-u.ac.jp)
Subjects: X-ray, Star, Transient
XRISM/Xtend Transient Search (XTS) detected an X-ray flare from an X-ray source XRISM J0915+4102on 2025-10-21 TT. The source position is determined to be (R.A., Dec.) = (138.787, 41.035), with a systematic error of ∼ 40 arcsec. One plausible counterpart is Pul -3 540245 which corresponds to an infrared source 2MASS J09150912+4101386. Pul -3 540245 is located ∼ 27arcsec apart from the position of XRISM J0915+4102.
The observation began at 2025-10-21 at ∼ 04:02. The flare was already active at that time. The flare reached its peak on 2025-10-21 at ∼ 05:42.
The peak flux is calculated as 9 × 10-13 erg s-1 cm-2 (0.4 – 10.0 keV). A systematic error of roughly 20% should be added to the statistical error. The corresponding luminosity is 2 × D1300pc2 × 1031 erg s-1 by assuming the distance to XRISM J0915+4102 of D1300pc.
We derived the above systematic error for the flux by comparing our derived values for the sources detected with XTS in several observations with those for the corresponding X-ray counterparts. We estimated the systematic error for the source position from the separations between the detected sources with the corresponding counterparts in the same field of view.
