MAXI/GSC detects a new activity from Be pulsar A0535+262
ATel #2970; T. Mihara (RIKEN), M. Nakajima (Nihon U.), T. Yamamoto, M. Sugizaki, M. Suzuki, Y. E. Nakagawa, T. Sootome, M. Matsuoka (RIKEN), N. Kawai, M. Morii, K. Sugimori, R. Usui (Tokyo Tech), K. Kawasaki, S. Ueno, H. Tomida, M. Kohama, M. Ishikawa (JAXA), A. Yoshida, K. Yamaoka, S. Nakahira (AGU), H. Tsunemi, M. Kimura (Osaka U.), H. Negoro, H. Ozawa, F. Suwa (Nihon U.), Y. Ueda, N. Isobe, S. Eguchi, K. Hiroi (Kyoto U.), A. Daikyuji (Miyazaki U.), A. Uzawa, T. Matsumura, K. Yamazaki (Chuo U.) report on behalf of the MAXI team
on 25 Oct 2010; 21:33 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
An increase of X-ray flux of the Be/X-ray binary pulsar A0535+26 has
been observed with MAXI/GSC since 2010 October 14.
The current activity is clearly out of the outburst phase
(only 0.7 x ~110-day orbital period since the last outburst peak), and
probably is a precursor activity.
Assuming that it is a precursor,
this is the fifth detection of the consecutive activities
following the ~110-day orbital cycle (Moritani+ 2010),
although the average interval of the last four
outbursts has been significantly longer at about 115 days.
Assuming this 115-day outburst period, the series of outbursts and
precursor events observed by MAXI took place at same phases,
~0.2 and ~0.95 respectively, where the phase zero is taken at MJD 55153.5,
the periastron passage prior to the previous giant outburst
(Atel #2324, #2336, #2337, #2343).
This change in outburst period may indicate
a secular change in the size, density, or orientation
(possibly precession) of the circumstellar disk of
the companion Be star.
The latest light curve and folded light curve are available at the
following URL: http://maxi.riken.jp/top/index.php?cid=1&jname=J0538+263 and also in
the news page URL:http://maxi.riken.jp/news/.