XRISM/Xtend Transient Search (XTS) detected an X-ray flare from a T Tauri star CVSO 751
ATel #17404; R. Takemoto (U. of Miyazaki), 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), 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.), S. Takatuska (UOsaka), Y. Terada (Saitama U.), Y. Terashima (Ehime U.), Y. Tsuboi (Chuo U.), H. Uchida (Kyoto U.), M. Yoshimoto (Ehime U.)
on 20 Sep 2025; 05:34 UT
Credential Certification: Kotaro Fukushima (kxfukushima@gmail.com)
Subjects: X-ray, Transient, Variables, Young Stellar Object
XRISM/Xtend Transient Search (XTS) detected an X-ray flare from an X-ray source XRISM J0525+0135 on 2025-09-17 TT. The source position is determined to be (R.A., Dec.) = (81.292, 1.599) with a systematic error of ∼ 40 arcsec. One of the plausible counterparts is a T Tauri star CVSO 751 at 300 pc, also catalogued as Gaia DR3 3222257471038421504, which is located ∼ 3 arcsec apart from the position of XRISM J0525+0135. All statistical uncertainties in this report are provided at a 90% confidence level unless stated otherwise.
The flare started on 2025-09-17 at around 08:24 – 08:43 TT and reached its peak on 2025-09-17 at around 09:48 – 10:25 TT. The flare exponentially decayed in (1.5 +/- 0.2) × 104 sec. The peak flux is calculated as 6.5 × 10-12 erg s-1 cm-2, which is derived by fitting the 0.4 – 2.0 keV light curve with a constant + burst model in the QDP software package. A systematic error of roughly 20% should be added to the statistical error. The corresponding luminosity is 7 × D300pc2 × 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 and their corresponding counterparts in the same field of view.
