2017MNRAS.468.3289Y

We derive the Sun's offset from the local mean Galactic plane (z_☉) using the observed z-distribution of young pulsars. Pulsar distances are obtained from measurements of annual parallax, H Iabsorption spectra or associations where available and otherwise from the observed pulsar dispersion and a model for the distribution of free electrons in the Galaxy. We fit the cumulative distribution function for a sech²(z)-distribution function, representing an isothermal self-gravitating disc, with uncertainties being estimated using the bootstrap method. We take pulsars having characteristic age τ_c <= 10^6.5 yr and located within 4.5 kpc of the Sun, omitting those within the local spiral arm and those significantly affected by the Galactic warp, and solve for z_☉ and the scaleheight, H, for different cut-offs in τ_c. We compute these quantities using just the independently determined distances and these together with dispersion measure (DM)-based distances separately using the YMW16 and NE2001 Galactic electron density models. We find that an age cut-off at 10^5.75 yr with YMW16 DM distances gives the best results with a minimum uncertainty in z_☉ and an asymptotically stable value for H showing that, at this age and below, the observed pulsar z-distribution is dominated by the dispersion in their birth locations. From this sample of 115 pulsars, we obtain z_☉ = 13.4 ± 4.4 pc and H = 56.9 ± 6.5 pc, similar to estimated scaleheights for OB stars and open clusters. Consistent results are obtained using the independent-only distances and using the NE2001 model for the DM-based distances.