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ATEL # 2277; M.Sugizaki (Riken), T.Mihara (Riken), N.Kawai (Tokyo tech.), M.Nakajima (Nihon-u), M.Matsuoka (JAXA) and the MAXI team.
on 31 Oct 2009; 6:46 UT
Password Certification: Tatehiro Mihara (email@example.com)
Subjects: X-ray, Request for Observations, Binaries, Neutron Stars, Pulsars, Transients
MAXI/GSC detected a renewed activity of Be/X-ray binary pulsar A0535+26 starting at October 21, 2009 (MJD 55125), and is still detectable at about 10 mCrab on October 30. The latest outburst, first reported by Fermi/GBM on July 26 (ATel #2142) was also detected by MAXI/GSC until it decayed to <10 mCrab at the end of August. The source was not significantly detected from August 30 to September 7, and from October 3 to October 20 with a typical 3-sigma one-day upper limit of 10 mCrab, except for a possible 3-sigma detection on October 16 at 10 mCrab. The MAXI exposure of A0535+26 was low on other dates in September and October. Note that the onset of the current activity on October 21 is 43 days earlier than the periastron passage, and is still earlier in the binary phase than any of the previous four series of onsets.