Nature of Eclipsing Pulsars

We present a model for pulsar radio eclipses in some binary systems, and testthis model for PSRs B1957+20 and J2051-0827. We suggest that in these binariesthe companion stars are degenerate dwarfs with strong surface magnetic fields.The magnetospheres of these stars are permanently infused by the relativisticparticles of the pulsar wind. We argue that the radio waves emitted by thepulsar split into the eigenmodes of the electron-positron plasma as they enterthe companion's magnetosphere and are then strongly damped due to cyclotronresonance with the ambient plasma particles. Our model explains in a naturalway the anomalous duration and behavior of radio eclipses observed in suchsystems. In particular, it provides stable, continuous, and frequency-dependenteclipses, in agreement with the observations. We predict a significantvariation of linear polarization both at eclipse ingress and egress. In thispaper we also suggest several possible mechanisms of generation of the opticaland $X$-ray emission observed from these binary systems.Comment: 12 pages, 5 figures, submitted to Ap