The radio nebula surrounding the Vela pulsar

Abstract

We have discovered that the radio nebula surrounding the Vela pulsar covers a much wider extent than previously reported, with two lobes to the north and south of the pulsar. Indications of this object have been reported previously, but its symmetric morphology around the pulsar and other details had not been identified as they were hidden due to poor sensitivity to low spatial frequencies. The structure is highly polarized and the polarization vectors, once corrected for Faraday rotation, reveal symmetry with respect to the spin axis of the pulsar. The X-ray emission found by Chandra lies at the centre of this structure, in a region that has no detectable excess of radio emission. We estimate total fluxes and regional fluxes from the northern and southern lobes, plus the X-ray region at four radio frequencies: 1.4, 2.4, 5 and 8.5 GHz. We present the corresponding images in both the total and polarized intensities, as well as those showing the derotated linear polarization vectors.