V. Boriakoff

High-sensitivity observations of 28 pulsars

Average 430-MHz pulse profiles and, where possible, modulation indices and pulse-nulling fractions are computed for 28 pulsars. Morphological classifications are determined for most of the pulsars. It is found that core emission components tend to have lower modulation indices than conal components, and that pulsars having only a core component never exhibit pulse pulling. PSR 1612 + 07 is shown to undergo mode changes.

The Electron Density in the Plane of the Galaxy

Pulsars provide probably the best probes of electron density in the plane of the Galaxy. The dispersion measure, the path integral of electron density along the line of sight from the pulsar to Earth, ∫ neds, is directly measurable from multi-frequency pulse-timing observations. The distance to a pulsar, d, can be estimated from its HI absorption and emission spectra. The mean electron density along the line of sight is then just = ∫ neds/d.