Renewed Activity from A 0535+26
ATel #595; Mark H. Finger (National Space Science and Technology Center/USRA)
on 27 Aug 2005; 19:58 UT
Distributed as an Instant Email Notice Transients
Credential Certification: Dr. Mark H. Finger (Mark.Finger@msfc.nasa.gov)
Subjects: X-ray, Binary, Neutron Star, Transient, Pulsar
A short observation of A 0535+26 on August 26.7 with the RXTE/PCA shows this nearby Be/X-ray pulsar at a flux of approximately 20 mCrab (2-10 keV). Pulsations consistent with a period of ~103 s were present, as was a high level of aperiodic variability.
The source had a major outburst in May and June 2005 which, because of the closeness of the sun, was observed by only a few instruments (ATEL #504, ATEL #557). In the RXTE/ASM light-curve A0535+26 was detected from May 6th to June 24, and had a peak flux above 103 c/s (1.4 Crab). A PCA observation on July 27.0 found a flux of about 2 mCrab (2-10 keV).
The recent PCA detection is approximately one orbital period (111 days, Motch et al. 1991, ApJ 369, 490) after the June 24 ASM detection. Another major outburst is possible. Further observations are scheduled with RXTE, and observations with other instruments are encouraged.