Wide Integrated Pulse Profiles of Pulsars

Abstract

In most pulsars the width of the integrated pulse profiles at half the peak intensity is about 3% of the period, and significant emission is not observed outside the immediate vicinity of this pulse. We are here referring to the intrinsic pulse width, unaffected by scattering in the interstellar medium. Notable exceptions are pulsars with two narrow pulses in the integrated profile separated by about half of a pulse period; it is customary to call the less significant pulse an interpulse and the stronger one a main pulse. The Crab pulsar, PSR0531 + 21, has an interpulse which is comparable in intensity to the main pulse¹, whereas PSR0823 + 26 (this letter), PSR0904 + 77 (ref. 2), PSR0950 + 08 (ref. 3), PSR1055 − 51 (ref. 4), and PSR1929 + 10 (ref. 5) have relatively weak interpuises. In this communication we draw attention to several pulsars which emit over large fractions of their pulse period and consequently represent a fundamental aspect of pulsar radiation which needs to be considered in future pulsar models.