XRISM/Xtend Transient Search (XTS) detected an X-ray burst and possible outburst on KS 1741-293
ATel #17348; C. Kang (Ehime U.), M. Shidatsu (Ehime U.), 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.), 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.), H. Sugai (Chuo U.), H. Takahashi (Hiroshima U.), T. Takagi (Ehime U.), S. Takatuska (UOsaka), R. Takemoto (U. of Miyazaki), Y. Terada (Saitama U.), Y. Terashima (Ehime U.), Y. Tsuboi (Chuo U.), H. Uchida (Kyoto U.), M. Yoshimoto (Ehime U.)
on 22 Aug 2025; 12:40 UT
Credential Certification: Megumi Shidatsu (shidatsu.megumi.wr@ehime-u.ac.jp)
Subjects: X-ray, Binary, Neutron Star, Transient
Referred to by ATel #: 17357
XRISM/Xtend Transient Search (XTS) detected X-ray activities from a neutron star low-mass X-ray binary KS 1741-293 in the observation conducted for 53 ks from 2025-08-20 to 2025-08-21 TT. The source position is determined to be (R.A., Dec.) = (266.208, -29.341), with a systematic error of ~40 arcsec. All statistical uncertainties in this report are provided as a 90% confidence level unless stated otherwise.
An X-ray burst from the source was detected on 2025-08-20 UT 07:51, lasting about 100 seconds. During the last 44 ks of the observation, after the X-ray burst, the flux was ~1.1 × 10-10 erg s-1 cm-2 (2.0 - 10.0 keV). This flux is lager than the flux in quiescence of <~ 1 × 10-13 (Degenaar et al. 2012, A&A, 545, 49). The averaged spectrum can be reproduced by an absorbed power-law model with a photon index and a column density of 1.63 +/- 0.11 and 1.77 (+0.10/-0.09) × 1023 cm-2, respectively.
