XRISM/Xtend Transient Search (XTS) detected an X-ray flare from ATO J079.1066-00.5215
ATel #17741; Y. Motogami (Saitama U.), H. Noda (Tohoku U.), 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), M. Mizumoto (UTEF), K. Mori (U. of Miyazaki), T. Narita (RIKEN), M. Nobukawa (NUE), S. Ogawa (TUS), Y. Sakamoto (Tohoku U.), M. Shidatsu (Ehime U.), H. Takahashi (Hiroshima U.), T. Takagi (Ehime U.), S. Takatsuka (UOsaka), 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 6 Apr 2026; 07:57 UT
Credential Certification: Hirofumi Noda (hirofumi.noda@astr.tohoku.ac.jp)
Subjects: X-ray, Star, Transient
XRISM/Xtend Transient Search (XTS) detected an X-ray flare from an X-ray source XRISM J0516-0031 on 2026-04-05 TT. The source position is determined to be (R.A., Dec.) = (79.101, -0.523), with a systematic error of ~ 40 arcsec. One of the plausible counterparts is a high-proper motion star ATO J079.1066-00.5215 which corresponds to an X-ray source 1eRASS J051625.2-003114. ATO J079.1066-00.5215 is located ~ 22 arcsec apart from the position of XRISM J0516-0031. All statistical uncertainties in this report are provided as a 90% confidence level unless stated otherwise.
The flare started at 2026-04-05 at ∼ 04:57 TT. The flare reached its peak on 2026-04-05 at ∼ 06:37. The flare exponentially decayed in 3 × 103 sec.
The peak flux is calculated as 5 × 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. The corresponding luminosity is 1 × D44pc2 × 1030 erg s-1 by assuming the distance to XRISM J0516-0031 of D44pc.
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.
