Pulsar bow-shock nebulae - II. Hydrodynamical simulation

We present hydrodynamical simulations, using a 2-D two component model (ambient medium and pulsar wind have different specific heat ratios), of bow shocks in a representative regime for pulsar wind driven bow-shock nebulae. We also investigate the behaviour of a passive toroidal magnetic field wound around the pulsar velocity direction. Moreover we estimate the opacity of the bow-shock to penetration of ISM neutral hydrogen: this quantity affects observable properties of the nebula, like its size, shape, velocity and surface brightness distribution. Finally we compare these numerical results with those from an analytical model. The development of more realistic models is needed in order to tune the criteria for searches of new such objects, as well as to interpret data on the known objects.