On the distribution of pulsars in the galactic plane

The spatial distribution of the projections of pulsars on the galactic plane within distances less than 5 kpc has been studied by looking for a correlation of these objects with the projections of the H II regions of best known distances. A significant correlation appears when pulsar distances are calculated from the dispersion measures by using a mean interstellar electron density = 0.03 cm-3, taken as uniform within the solar neighbourhood considered. This correlation remains for models in which the electron density increases toward the galactic centre. The resultung spatial correlation of pulsars with the galactic spiral arms in the vicinity of the Sun indicates that pulsars are generated from young objects, and allows us to estimate an upper limit for their mean lifetimes, which is in agreement with previous values. (orig.)