MAXI/GSC detection of a probable X-ray transient MAXI J2101-802

ATel #17186; 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, A. Yoshida (AGU), Y. Tsuboi, H. Sugai, N. Nagashima (Chuo U.), 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, K. Fujiwara (Kyoto U.), M. Yamauchi, M. Nishio, C. Hiraizumi (Miyazaki U.), K. Yamaoka (Nagoya U.), M. Sugizaki (Kanazawa U.), W. Iwakiri (Chiba U.), T. Kawamuro (Osaka U.), and S. Yamada (Tohoku U)
on 16 May 2025; 04:05 UT
Credential Certification: Hitoshi Negoro (negoro@phys.cst.nihon-u.ac.jp)

Tweet

The MAXI/GSC detects a faint uncatalogued X-ray transient source from 2025 May 15. Assuming that the source flux was constant over five transits from 12:55 UT on May 15 to 01:18 on May 16, we obtain the source position at

(R.A., Dec) = (315.308 deg, -80.221 deg) = (21 01 13, -80 13 15) (J2000)

with a 90% C.L. statistical error of 0.37 deg and an additional systematic uncertainty of 0.1 deg (90% containment radius). The X-ray flux averaged over the scans was 30 +- 6 mCrab (4.0-10.0 keV, 1 sigma error). The source flux is almost constant for the above period.

The source position is close to the edge of the detectors, which may cause a larger position uncertainty. Since there is no bright catalogued X-ray source around there, we tentatively name the source MAXI J2101-802.
.
Followup observations are encouraged.

Information of MAXI J2101-802