ar X iv : a st ro - p h / 05 02 50 3 v 1 2 4 Fe b 20 05 Orbital modulation of emission of the binary pulsar

In binary radio pulsar system J0737−3039, slow pulsar B shows orbital modulations of intensity, being especially bright at two short orbital phases. We propose that these modulations are due to distortion of pulsar B magnetosphere by pulsar A wind which produces orbital phase-dependent changes of the direction along which radio waves are emitted. In our model, pulsar B is intrinsically bright at all times but its radiation beam misses the Earth at most orbital phases. We employ a simple model of distorted B magnetosphere using stretching transformations of Euler potentials of dipolar fields. To fit observations we use parameters of pulsar B derived from modeling of A eclipses (Lyutikov & Thompson 2005). The model reproduces two bright regions approximately at the observed orbital phases, explains variations of the pulse shape between them and regular timing residuals within each emission window. It also makes predictions for timing properties and secular variations of pulsar B profiles.