XRISM/Xtend Transient Search (XTS) detected an X-ray flare possibly from X205211.81-570110.3
ATel #17779; S. Takatsuka (UOsaka), M. Mizumoto (UTEF), Y. Kanemaru, Y. Omiya, Y. Uchida, T. Yoneyama (JAXA), M. Audard (U. de Geneve), E. Behar (Technion), K. Fukushima (TUS), 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), A. Miyamoto (UOsaka), K. Mori (U. of Miyazaki), Y. Motogami (Saitama U.), T. Narita (RIKEN), M. Nobukawa (NUE), H. Noda (Tohoku U.), S. Ogawa (TUS), Y. Sakamoto (Tohoku U.), M. Shidatsu (Ehime U.), H. Takahashi (Hiroshima U.), T. Takagi (Ehime U.), F. Takisawa (Ehime U.), Y. Terada (Saitama U., JAXA), Y. Terashima (Ehime U.), Y. Tsuboi (Chuo U.), H. Uchida (Kyoto U.), A. Yoshimoto (NWU), M. Yoshimoto (Ehime U.)
on 8 May 2026; 06:43 UT
Credential Certification: Tomokage Yoneyama (tyoneyama263@g.chuo-u.ac.jp)
Subjects: X-ray, Star, Transient
XRISM/Xtend Transient Search (XTS) detected an X-ray flare from an X-ray source XRISM J2052-5701 on 2026-05-02 TT. The source position is determined to be (R.A., Dec.) = (313.049, -57.017) with a systematic error of ∼ 40 arcsec. The Chandra source X205211.81-570110.3 is located ∼ 7 arcsec apart from XRISM J2052-5701. A possible optical counterpart is Gaia DR3 6457472682313731840 with a distance of ∼ 140 pc, which is located ∼ 8 arcsec apart from XRISM J2052-5701. The angular separation between the Gaia source and the Chandra source X205211.81-570110.3 is 0.42 arcsec.
The flare started at 2026-05-02 09:39 TT and reached its peak on 2026-05-02 at around 10:13 TT. The flare exponentially decayed in 2 × 103 sec. The peak flux is calculated as 2 × 10-13 erg s-1 cm-2. A systematic error of roughly 20% should be taken into account. The corresponding luminosity is 5 × 1029 erg s-1 by assuming the distance of 140 pc.
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.
