NATURE OF ECLIPSING PULSARS

摘要

We present a model for pulsar radio eclipses in some binary systems and test this model for PSR B1957+20 and PSR J2051 --0827. We suggest that in these binaries the companion stars are degenerate dwarfs with strong surface magnetic fields. The magnetospheres of these stars are permanently infused by the relativistic particles of the pulsar wind. We argue that the radio waves emitted by the pulsar split into the eigenmodes of the electron-positron plasma as they enter the companion's magnetosphere and are then strongly damped because of cyclotron resonance with the ambient plasma particles. Our model explains in a natural way the anomalous duration and behavior of radio eclipses observed in such systems. In particular, it provides stable, continuous, and frequency-dependent eclipses, in agreement with the observations. We predict a significant variation of linear polarization both at eclipse ingress and at egress. In this paper we also discuss several possible mechanisms of generation of the optical and X-ray emission observed from these binary systems.