MAXI/GSC detection an onset of outburst from the Be/X-ray binary pulsar Cep X-4
ATel #6212; M. Nakajima, H. Negoro (Nihon U.), A. Kawagoe (Chuo U.), S. Ueno, H. Tomida, S. Nakahira, M. Kimura, M. Ishikawa, Y. E. Nakagawa (JAXA), T. Mihara, M. Sugizaki, M. Morii, M. Serino, J. Sugimoto, T. Takagi, A. Yoshikawa, M. Matsuoka (RIKEN), N. Kawai, T. Yoshii, Y. Tachibana (Tokyo Tech), A. Yoshida, T. Sakamoto, Y. Kawakubo, H. Ohtsuki (AGU), H. Tsunemi, D. Uchida (Osaka U.), K. Fukushima, T. Onodera, K. Suzuki (Nihon U.), Y. Ueda, M. Shidatsu, T. Kawamuro, T. Hori (Kyoto U.), Y. Tsuboi, (Chuo U.), M. Yamauchi, Y. Morooka (Miyazaki U.), K. Yamaoka (Nagoya U.) report on behalf of the MAXI team:
on 9 Jun 2014; 04:08 UT
Distributed as an Instant Email Notice Transients
Credential Certification: Motoki Nakajima (nakajima.motoki@nihon-u.ac.jp)
Subjects: X-ray, Binary, Neutron Star, Transient, Pulsar
On June 6, 2014, the MAXI Nova Alert System detected an X-ray flux increase at a position consistent with that a transient Be X-ray binary pulsar of Cep X-4 (= 4U2135+57 and Ginga 2138+56). This is the first detection of its activity by the GSC since MAXI started operations in August 2009. The source fluxes in the 2-10 keV energy band are 0.07 ± 0.03 count s-1 cm-2 (33 ± 14 mCrab) on June 6 (MJD 56814), and 0.11 ± 0.06 count s-1 cm-2 (50 ± 28 mCrab) on June 7 (MJD 56815). The Swift/BAT transient monitor also detected its brightening (40 ± 20 mCrab in 15-50 keV on June 7). The current activity is observed after an interval of 5 years (ATel #1956, #1972). The latest light curve and image of this source are updated daily at the following URL: http://maxi.riken.jp/sourcelist.html.