MAXI/GSC detected an X-ray increase on GT Mus from 2025-04-17 UT
ATel #17151; H. Sugai (Chuo U.), W. Iwakiri (Chiba U.), Y. Tsuboi, N. Nagashima (Chuo U.), H. Negoro, M. Nakajima, K. Takagi, H. Takahashi, K. Tatano, H. Nishio (Nihon U.), T. Mihara, T. Tamagawa, N. Kawai, M. Matsuoka (RIKEN), T. Sakamoto, M. Serino, S. Sugita, Y. Kawakubo, H. Hiramatsu, Y. Kondo, S. Sasao, A. Yoshida (AGU), M. Shidatsu, Y. Niida, C. Kang, T. Nakamoto (Ehime U.), I. Takahashi, M. Niwano, N. Higuchi, Y. Yatsu (Tokyo Tech), S. Nakahira, S. Ueno, H. Tomida, M. Ishikawa, S. Ogawa, M. Kurihara (JAXA), Y. Ueda, Y. K. Fujiwara (Kyoto U.), M. Yamauchi, M. Nishio, C. Hiraizumi (Miyazaki U.), K. Yamaoka (Nagoya U.), M. Sugizaki (Kanazawa U.), T. Kawamuro (Osaka U.), S. Yamada (Tohoku U), report on behalf of the MAXI team:
on 17 Apr 2025; 16:09 UT
Credential Certification: Yohko Tsuboi (tsuboi@phys.chuo-u.ac.jp)
Subjects: X-ray, Binary, Star, Transient, Variables
At 03:55 on 2025-04-17 UT, the MAXI/GSC nova alert system triggered on a source at a position consistent with that of an RS CVn star GT Mus.
The position is determined from the data at the triggered scan, as (R.A., Dec) = (174.889, -65.333 deg) = (11 39 33, -65 19 58) (J2000) with a statistical 90% C.L. elliptical error region with long and short radii of 0.30 deg and 0.1 deg, respectively. The roll angle of the long axis from the north direction is 92.0 deg counterclockwise.There is an additional systematic uncertainty of 0.1 deg (90% containment radius). This position is consistent with that of an RS CVn star GT Mus.
The flux is
4 × 10-10 erg s-1 cm-2 (2.0 – 20.0 keV) for the period from 00:00 on 2025-04-16 to 22:57 on 2025-04-17 UT, and the flare is still continuing. The flux corresponds to a luminosity of 6 × 1031 erg s-1 s -1 for an assumed distance of 110 pc.
