High-precision pulsar astrometry using the VLA and VLBA interferometers

Radio interferometry was used to determine the proper motions and parallaxes of several pulsars. Twenty-eight pulsars were observed with the Very Large Array over a seven year period, resulting in first or improved proper motion measurements for twenty-five pulsars. Wide-field imaging allowed background sources within each pulsar's field to be used in the construction of a local coordinate system on which the pulsar's motion was measured. Astrometric observations of ten pulsars were made with the Very Long Baseline Array. A new ionosphere calibration technique was applied to the new data. Eight new pulsar parallax measurements were made, more than doubling the number to date. Pulsar gating was used during both experiments to increase the sensitivity of the instruments.; These new results were used to determine the observed pulsar velocity distribution. A mean transverse velocity of 300 km s−1 best fits the data. This best fit suggests that a high velocity tail is not required to explain the observed motions of pulsars. The braking indices of pulsars were probed in the comparison of their kinetic and characteristic velocities. The data are consistent with dipole radiation being the main source of spin-down torque. The kinetic age data also suggest that magnetic fields of pulsars do not decay on time-scales shorter than 107 years. Finally, the velocity component perpendicular to the plane of the Galaxy was computed in order to determine the probability that each pulsar is falling towards the Galaxy. A Bayesian calculation suggests that the data are consistent with no young pulsars falling.