Pulsars

At the time of writing the number of known pulsars is 321. As will be described in more detail below, all of these pulsars are believed to be within the Galaxy. They constitute a very small fraction of the total number of pulsars in the Galaxy, but their intrinsic properties are probably reasonably representative of the total galactic population. In this section we describe the observed properties of the pulsed emission and some of the implications of these observations for models of the radiation mechanism. In Section II the techniques used to measure accurate pulsar periods are described. The observed variations in periods, including the secular increase, discontinuous changes and those due to binary motion, are described and their implications discussed. Finally, in Section III, the galactic distribution and evolution of pulsars is considered. (orig./WL)