PSR J1740+1000: A Young Pulsar Well Out of the Galactic Plane

We discuss PSR J1740+1000, one of five pulsars recently discovered in asearch of 470 square degrees at 430 MHz during the upgrade of the 305-m Arecibotelescope. The period of 154 ms and period derivative of 2.1 x 10^-14 s/s implya spin-down age of 114 kyr that is smaller than 95% of all known pulsars. Theyouth and proximity of this pulsar make it a good candidate for detection atX-ray and gamma-ray energies. Its high Galactic latitude of 20.4 degreessuggests a very high velocity if the pulsar was born in the midplane of theGalaxy and if its kinematic age equals its spindown age. Interstellarscintillations, however, suggest a much lower velocity. We discuss possibleexplanations for this discrepancy, taking into account (a) possible birth sitesaway from the midplane; (b) contributions from the unmeasured radial velocity;(c) a kinematic age different from the spin-down age; and (d) biasing of thescintillation velocity by enhanced scattering from the North Polar Spur.