13 research outputs found
Millisecond Pulsar Velocities
Get PDFWe present improved timing parameters for 13 millisecond pulsars (MSPs)
including 9 new proper motion measurements. These new proper motions bring to
23 the number of MSPs with measured transverse velocities. In light of these
new results we present and compare the kinematic properties of MSPs with those
of ordinary pulsars. The mean transverse velocity of MSPs was found to be
85+/-13 km/s; a value consistent with most models for the origin and evolution
of MSPs and approximately a factor of four lower than that of ordinary pulsars.
We also find that, in contrast to young ordinary pulsars, the vast majority of
which are moving away from the Galactic plane, almost half of the MSPs are
moving towards the plane. This near isotropy would be expected of a population
that has reached dynamic equilibrium. Accurate measurements of MSP velocities
have allowed us to correct their measured spin-down rates for Doppler
acceleration effects, and thereby derive their intrinsic magnetic field
strengths and characteristic ages. We find that close to half of our sample of
MSPs have a characteristic age comparable to or greater than the age of the
Galaxy.Comment: 10 pages LaTeX including 2 LaTeX tables and 3 postscript figures;
submitted to MNRA
