Flaring in Sax J1808.4–3658: Flow Instabilities near the Propeller Stage
نویسندگان
چکیده
We present a simultaneous periodic and aperiodic timing study of the accreting millisecond X-ray pulsar SAX J1808.4-3658. We analyze five outbursts of the source and for the first time provide a full and systematic investigation of the enigmatic phenomenon of the 1 Hz flares observed during the final stages of some of the outbursts. We show that strong links between pulsations and 1 Hz flares exist, and suggest they are related with hydrodynamic disk instabilities that are triggered close to the disk-magnetosphere boundary layer when the system is entering the propeller regime. Subject headings: stars: individual (SAX J1808.4−3658 ) — stars: neutron — X-rays: stars
منابع مشابه
The Luminosity and Energy Dependence of Pulse Phase Lags in the Accretion-powered Millisecond Pulsar Sax J1808.4−3658
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Soft phase lags, in which X-ray pulses in lower energy bands arrive later than pulses in higher energy bands, have been observed in nearly all accretion-powered millisecond pulsars, but their origin remains an open question. In a study of the 2.5 ms accretion-powered pulsar SAX J1808.4−3658, we report that the magnitude of these lags is strongly dependent on the accretion rate. During the brigh...
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