XRISM/Xtend Transient Search (XTS) detected an X-ray flare possibly from 1BMW 045320.6+025843
ATel #17695; Y. Motogami (Saitama U.), H. Noda (Tohoku U.), 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), H. Matsumoto (UOsaka), T. Matsushima (U. of Miyazaki), A. Miyamoto (UOsaka), M. Mizumoto (UTEF), K. Mori (U. of Miyazaki), N. Nagashima (Chuo U.), T. Narita (Kyoto U.), M. Nobukawa (NUE), Y. Sakamoto (Tohoku U.), M. Shidatsu (Ehime U.), H. Sugai (Chuo U.), H. Takahashi (Hiroshima U.), T. Takagi (Ehime U.), S. Takatsuka (UOsaka), R. Takemoto (U. of Miyazaki), Y. Terada (Saitama U., JAXA), Y. Terashima (Ehime U.), Y. Tsuboi (Chuo U.), H. Uchida (Kyoto U.), A. Yoshimoto (NWU), M. Yoshimoto (Ehime U.), A. Sarkar (U. of Arkansas)
on 23 Feb 2026; 15:12 UT
Credential Certification: Hirofumi Noda (hirofumi.noda@astr.tohoku.ac.jp)
Subjects: X-ray, Binary, Star, Transient, Young Stellar Object
XRISM/Xtend Transient Search (XTS) detected an X-ray flare from an X-ray source XRISM J0453+0259 on 2026-02-22 TT. The source position is determined to be (R.A., Dec.) = (73.339, +2.979), with a systematic error of ∼ 40 arcsec. One of the plausible counterparts is 1BMW 045320.6+025843, located ∼ 11 arcsec apart from the position of XRISM J0453+0259.
The flare started at 2026-02-22 at ∼ 01:47 TT. The flare reached its peak on 2026-02-22 at ∼ 02:38. The flare exponentially decayed in 104 sec.
The peak flux is calculated as 3 × 10-12 erg s-1 cm-2 (0.4 - 10.0 keV). A systematic error of roughly 20% should be added to the statistical error.
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.
