MAXI/GSC observation of the onset of the giant outburst from the Be/X-ray binary pulsar 4U 0115+63
ATel #16573; M. Nakajima, H. Negoro, K. Kobayashi, M. Tanaka, Y. Soejima, Y. Kudo (Nihon U.), T. Mihara, T. Kawamuro, S. Yamada, S. Wang, T. Tamagawa, N. Kawai, M. Matsuoka (RIKEN), T. Sakamoto, M. Serino, S. Sugita, Y. Kawakubo, H. Hiramatsu, H. Nishikawa, Y. Kondo, A. Yoshida (AGU), Y. Tsuboi, E. Goto, H. Sugai, N. Nagashima (Chuo U.), M. Shidatsu, Y. Niida (Ehime U.), I. Takahashi, M. Niwano, S. Sato, N. Higuchi, Y. Yatsu (Tokyo Tech), S. Nakahira, S. Ueno, H. Tomida, M. Ishikawa, S. Ogawa, T. Kurihara (JAXA), Y. Ueda, K. Setoguchi, T. Yoshitake, Y. Nakatani, Y. Okada (Kyoto U.), M. Yamauchi, Y. Hagiwara, Y. Otsuki, T. Hasegawa, M. Nishio (Miyazaki U.), K. Yamaoka (Nagoya U.), M. Sugizaki (NAOC), W. Iwakiri (Chiba U.)
on 5 Apr 2024; 12:48 UT
Credential Certification: Motoki Nakajima (nakajima.motoki@nihon-u.ac.jp)
Subjects: X-ray, Binary, Neutron Star, Transient, Pulsar
The MAXI/GSC nova alert system triggered an X-ray brightening from the Be/X-ray binary pulsar 4U 0115+63 on 2024 March 28 (MJD 60397). Before this brightening, MAXI/GSC observed three X-ray outbursts from this source after the historical giant X-ray outburst in 2023 March (ATel#15975, #15978, #15989) on 2023 November 27 (MJD 60275), 2024 January 15 (MJD 60324), and 2024 February 10 (MJD 60350). Since each outburst had started after the periastron passage, these events are classified as the normal outburst (Reig 2011). The current outburst also started from the periastron, but the flux increase rate and the latest luminosity exceeds the previous three events. The 5-12 keV flux increased with the average rate of ~0.027 photons/s/cm2/day between March 30 and April 4, and reached 0.168 ± 0.020 photons/fs/cm2 (179 ± 21 mCrab) on April 4 (MJD 60404). This outburst behavior traces the giant outburst profile in 1999 and 2008 observed by RXTE (e.g. Boldin et al. 2013). So, this outburst might develop into a giant outburst since 2023 March (ATel#15967,#15975,#15978,#15989). We encourage multi-wavelength observations to monitor this source.
The latest X-ray light-curve can be checked at the following pages;
MAXI ( http://maxi.riken.jp/v7l3h/J0118+637/index.html ),
Swift/BAT ( https://swift.gsfc.nasa.gov/results/transients/weak/4U0115p634/ ),
Fermi/GBM ( https://gammaray.nsstc.nasa.gov/gbm/science/pulsars/lightcurves/4u0115.html ), and
the BeXRB monitor page ( http://integral.esac.esa.int/bexrbmonitor/Plots/sim_plot_4U0115+63.html ).
light curve of x-ray outbursts
