MAXI/GSC detection of an X-ray burst from KS 1741-293
ATel #17357; M. Shidatsu (Ehime U.), W. Iwakiri (Chiba U.), K. Yamaoka (Nagoya U.), H. Negoro (Nihon U.), M. Serino (AGU), M. Nakajima, K. Takagi, H. Takahashi, K. Tatano, H. Nishio (Nihon U.), T. Mihara, T. Tamagawa, N. Kawai, M. Matsuoka (RIKEN), T. Sakamoto, S. Sugita, Y. Kawakubo, H. Hiramatsu, Y. Kondo, A. Yoshida (AGU), Y. Tsuboi, H. Sugai, N. Nagashima (Chuo U.), C. Kang, T. Nakamoto (Ehime U.), I. Takahashi, Y. Yatsu (Science Tokyo), S. Nakahira, S. Ueno, H. Tomida, M. Ishikawa, S. Ogawa, M. Kurihara (JAXA), Y. Ueda, K. Fujiwara (Kyoto U.), M. Yamauchi, M. Nishio, C. Hiraizumi (Miyazaki U.), M. Sugizaki (Kanazawa U.), T. Kawamuro (Osaka U.), S. Yamada (Tohoku U) report on behalf of the MAXI team:
on 23 Aug 2025; 05:48 UT
Credential Certification: Megumi Shidatsu (shidatsu.megumi.wr@ehime-u.ac.jp)
Subjects: X-ray, Binary, Neutron Star, Transient, Variables
The MAXI/GSC nova alert system detected an X-ray burst from a source in the Galactic center region
at 2025 August 22 12:02 UT. Assuming that the source flux was constant over the transit,
we obtain the source position at
(R.A., Dec) = (266.134 deg, -29.493 deg) = (17 44 32, -29 29 34) (J2000)
with a statistical 90% C.L. elliptical error region
with long and short radii of 0.17 deg and 0.15 deg, respectively.
The roll angle of long axis from the north direction is 163.0 deg counterclockwise.
There is an additional systematic uncertainty of 0.1 deg (90% containment radius).
This position is consistent with the low-mass X-ray binary KS 1741-293, from which
the XRISM Xtend Transient Search team recently reported a new outburst and an X-ray burst (ATel #17348).
The X-ray flux averaged over the scan was estimated to be 636 +- 52 mCrab
(4.0-10.0keV, 1 sigma error), although this value may be overestimated
due to contamination from Galactic diffuse emission and nearby sources.
There was no significant excess flux in the previous transit at 10:29 UT
and in the next transit at 13:35 UT.
