The Vela Pulsar's Proper Motion and Parallax Derived from VLBI Observations

The Vela pulsar is the brightest pulsar at radio wavelengths. It was the object that told us (via its glitching) that pulsars were solid rotating bodies not oscillating ones. Along with the Crab pulsar, is it the source of many of the models of pulsar behavior. Therefore it is of vital importance to know how far away it is and its origin. The proper motion and parallax for the Vela pulsar have been derived from 2.3 and 8.4 GHz very long baseline interferometry (VLBI) observations. The data span 6.8 years and consist of 11 epochs. We find a proper motion of μα cos δ = -49.68 ± 0.06, μδ = 29.9 ± 0.1 mas yr-1 and a parallax of 3.5 ± 0.2 mas, which is equivalent to a distance of 287img1.gif pc. When we subtract out the Galactic rotation and solar peculiar velocity, we find μ* = 45 ± 1.3 mas yr-1 with a position angle of 301° ± 1fdg8 which implies that the proper motion has a small but significant offset from the X-ray nebula's symmetry axis.