Distribution of free electrons in the galactic plane

A method is proposed for constructing a map of the electron density distribution in the galactic plane. Data on the dispersion measures DM of more than 1500 pulsars and their distances, found by an independent method, are used. The independent distances of the pulsars are estimated using an empirical relation of the form L=gamma P-alpha(P)over dot(beta)W(delta) between the radio luminosity L of the pulsars and their periods P, the rate of change (P)over dot. of their periods, and the half width W of their pulses. A map of the electron density distribution in the galactic plane within a +/- 400 pc layer is provided.