XRISM/Xtend Transient Search (XTS) detected an X-ray flare possibly from an M dwarf star
ATel #17071; T. Yoneyama (Chuo U.), K. Fukushima, K. Hayashi, Y. Kanemaru, S. Ogawa, T. Yoshida (JAXA), M. Audard (U. de Geneve), E. Behar (Technion), S. Inoue (Kyoto U.), Y. Ishihara (Chuo U.), T. Kohmura (TUS), Y. Maeda (JAXA), M. Mizumoto (UTEF), N. Nagashima (Chuo U.), M. Nobukawa (NUE), K. Pottschmidt (UMBC, NASA GSFC, CRESST), M. Shidatsu (Ehime U.), H. Sugai (Chuo U.), Y. Terada (Saitama U.), Y. Terashima (Ehime U.), Y. Tsuboi (Chuo U.), H. Uchida (Kyoto U.), T. Yanagi (Chuo U.), , M. Yoshimoto (Osaka U.)
on 10 Mar 2025; 08:51 UT
Credential Certification: Tomokage Yoneyama (tyoneyama263@g.chuo-u.ac.jp)
Subjects: X-ray, Star, Transient, Variables
XRISM/Xtend Transient Search (XTS) detected an X-ray flare from an X-ray source XRISM J1748-2832 on 2025-03-09 TT. The source position is determined to be (R.A., Dec.) = (266.890 -28.538), with a systematic error of ∼ 40 arcsec. A plausible counterpart is an X-ray source CXOGCS J174734.5-283215, a potential M dwarf star located ∼ 14 asec apart from the position of XRISM J1748-2832. Another counterpart candidate is a YSO candidate SPICY 64348 located ∼ 21 arcsec apart from XRISM J1748-2832. Distances to CXOGCS J174734.5-283215 and SPICY 64348 are ∼ 590 and ∼ 500 pc, respectively by Gaia DR3.
The flare started on 2025-03-09 at 06:25 TT, rapidly peaked at 06:31 TT, and then exponentially decayed in ∼ 3 ksec. The timing properties are derived by fitting the 0.4 – 2.0 keV light curve with a constant + burst model in the QDP software package.
The flux at the flare phase is calculated as 1.2 × 10-12 erg s-1 cm-2 (0.4 – 2.0 keV). A systematic error of roughly 20% should be added to the statistical error. Corresponding luminosity is 5.1 D2590 pc × 1031 erg s-1.
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.
