MAXI/GSC detection of a new X-ray outburst from M15
ATel #15586; H. Negoro (Nihon U.), M. Serino (AGU), M. Nakajima, K. Kobayashi, M. Tanaka, Y. Soejima (Nihon U.), T. Mihara, T. Kawamuro, S. Yamada, T. Tamagawa, M. Matsuoka (RIKEN), T. Sakamoto, S. Sugita, H. Hiramatsu, A. Yoshida (AGU), Y. Tsuboi, W. Iwakiri, J. Kohara (Chuo U.), M. Shidatsu, M. Iwasaki (Ehime U.), N. Kawai, M. Niwano, R. Hosokawa, Y. Imai, N. Ito, Y. Takamatsu (Tokyo Tech), S. Nakahira, S. Ueno, H. Tomida, M. Ishikawa, T. Kurihara (JAXA), Y. Ueda, S. Ogawa, K. Setoguchi, T. Yoshitake, K. Inaba (Kyoto U.), M. Yamauchi, T. Sato, R. Hatsuda, R. Fukuoka, Y. Hagiwara, Y. Umeki (Miyazaki U.), K. Yamaoka (Nagoya U.), Y. Kawakubo (LSU), and M. Sugizaki (NAOC)
on 3 Sep 2022; 04:44 UT
Credential Certification: Hitoshi Negoro (negoro@phys.cst.nihon-u.ac.jp)
Subjects: X-ray, Black Hole, Neutron Star, Transient
At 21:46 UT on 2022 August 26, the MAXI/GSC nova alert system triggered on a new X-ray outburst probably from an X-ray source in the globular cluster M15. The X-ray flux averaged over 13 scan transits from 22:33 on August 25 and 21:46 August 26 scan was 28 +- 5 mCrab (4.0-10.0keV, 1 sigma error). We note that the GSC detects persistent emission from M15 at about 10 mCrab. The outburst likely started between 2022 August 4 and August 22 when the source was in a sky region undetectable with fine cameras. On August 29, the source flux peaked at 0.083 +/- 0.013 photons/cm2/s (~ 40 mCrab) and 0.054 +/- 0.009 photons/cm2/s (~ 43 mCrab) in the 2-4 and 4-10 keV bands, respectively.
This is the 4th detection of outbursts from M15 since 2009 for MAXI. The previous outbursts started around MJD 55400 (2010 July 23), 55655 (2011 April 4, ATel #3356), and 56510 (2013 August 6, ATel #5327). In the latter two outbursts, followup observations revealed the outbursts originated from M15 X-2 (ATel #3363, #3378, #3393, #5396, #5490). M15 is known to have the X-ray sources, AC211, X-2, and X-3.
The Swift/XRT followup observation is planed, and further followup observations are encouraged to identify the source in outburst.
MAXI data for M15
