MAXI/GSC detection of a new X-ray outburst from GK Persei
ATel #15860; T. Mihara (RIKEN), H. Negoro (Nihon U.), W. Iwakiri (Chiba U.) M. Nakajima, K. Kobayashi, M. Tanaka, Y. Soejima (Nihon U.), T. Kawamuro, S. Yamada, T. Tamagawa, M. Matsuoka (RIKEN), T. Sakamoto, M. Serino, S. Sugita, H. Hiramatsu, H. Nishikawa, A. Yoshida (AGU), Y. Tsuboi, J. Kohara, S. Urabe, S. Nawa, N. Nemoto (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, Y. Nakatani (Kyoto U.), M. Yamauchi, T. Sato, R. Hatsuda, R. Fukuoka, Y. Hagiwara, Y. Umeki (Miyazaki U.), K. Yamaoka (Nagoya U.), Y. Kawakubo (LSU), M. Sugizaki (NAOC) report on behalf of the MAXI team:
on 15 Jan 2023; 02:34 UT
Credential Certification: Tatehiro Mihara (mihara@crab.riken.jp)
Subjects: X-ray, Binary, Cataclysmic Variable, Nova, Transient
The MAXI/GSC nova alert system triggered on an X-ray transient positionally consistent
with the dwarf nova cataclysmic variable GK Persei at 15:24 UT on January 3, 2023 (MJD 59947).
Because the source region was not observed with the GSC from December 4, 2022 to January 1, 2023,
the onset of the outburst is not clear from the MAXI data.
However, Swift/BAT data (https://swift.gsfc.nasa.gov/results/transients/weak/GKPer/
) show the onset of the outburst was around December 21, 2022 (MJD 59934).
The 2-4 keV and 4-10 keV GSC count rates on January 3 were 0.008 +/- 0.010 photons/cm2/s
(~4 mCrab) and 0.024 +/- 0.010 photons/cm2/s (~19 mCrab), respectively.
Although the source flux tends to decrease, the source still stays in the flat top of the outburst.
Shore et al. (ATel #15858) also reported the results of the latest optical observations of this outburst.
This is the fourth outburst that MAXI clearly detected since 2009. The previous MAXI detection
of the outbursts were on March 6 to June 3, 2010 (MJD 55261-55350),
April 19 to May 20, 2015 (MJD 57131-57162),
and August 23 to September 30, 2018 (MJD 58353-58391).
Since there were sometimes lack of observations before or after the span,
the dates above do not mean the outburst span.
The X-ray outbursts were flat top of about 15 mCrab (4-10 keV) for several tens of days.
