XRISM/Xtend Transient Search (XTS) detected an X-ray outburst from a high-mass X-ray binary AX J1910.7+0917
ATel #16607; T. Yoshida, K. Fukushima, K. Hayashi, Y. Kanemaru, S. Ogawa (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), M. Nobukawa (NUE), K. Pottschmidt (UMBC, NASA GSFC, CRESST), M. Shidatsu (Ehime U.), Y. Terada (Saitama U.), Y. Terashima (Ehime U.), Y. Tsuboi (Chuo U.), H. Uchida (Kyoto U.), T. Yoneyama (Chuo U.), M. Yoshimoto (Osaka U.)
on 1 May 2024; 15:11 UT
Credential Certification: Tomokage Yoneyama (tyoneyama263@g.chuo-u.ac.jp)
Subjects: X-ray, Binary, Neutron Star, Transient, Variables, Pulsar
XRISM/Xtend Transient Search (XTS) detected an X-ray outburst from a high-mass X-ray binary AX J1910.7+0917 on 2024-04-28 TT. Due to a bad time interval of XRISM, the outburst start time was not detected, but only a rough constraint, 2024-04-28 19:52 – 20:41 TT, is given. The outburst continues in the latest observation data of XRISM (2024-04-30 05:25 TT).
The spectrum in the outburst phase is reproduced with an absorbed power-law model with the absorption of NH = 5.6 (+0.4/-0.5) × 1022cm-2 (90% confidence level) and the photon index of Γ = 1.5 (+0.1/-0.2). We obtain the model flux of (3.6 +0.4/-0.2) × 10-11 erg s-1cm-2 (0.4 – 10.0 keV). A systematic error of roughly 20% should be added to the statistical error. Corresponding luminosity is 1.1 (+/-0.1) × 1036 erg s-1 by assuming the distance to AX J1910.7+0917 is 16 kpc. The luminosity is comparable to that observed by XMM-Newton in 2004 (Sidoli et al. 2017), which is the brightest outburst ever.
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.
