PSR J1740+1000: A young pulsar well out of the Galactic plane

We discuss PSR J1740-1000, one of five pulsars recently discovered in a search of 470 deg(2) at 430 MHz during the upgrade of the 305 m Arecibo Telescope. The period P=154 ms and period derivative (P)over dot =2.1x10(-14) s s-(1) imply a spin-down age tau(s) = P/2(P)over dot kyr that is smaller than 95% of all known pulsars. The youth and proximity of this pulsar make it a good candidate for detection at X-ray and gamma-ray energies. Its high Galactic latitude (b=20degrees.4) suggests a very high velocity if the pulsar was born in the midplane of the Galaxy and if its kinematic age equals its spin-down age. Interstellar scintillations, however, suggest a much lower velocity. We discuss possible explanations for this discrepancy, taking into account (1) possible birth sites away from the midplane; (2) contributions from the unmeasured radial velocity; (3) a kinematic age different from the spin-down age; and (4) biasing of the scintillation velocity by enhanced scattering from the North Polar Spur.