Rapidly Pulsing Radio Sources

Abstract

Observations of a new type of rapidly varying radio source have recently been reported¹. The principal characteristics of the four sources so far discovered may be summarized as follows—sharp pulses of radiation are received, separated by comparatively long intervals which themselves are remarkably constant (with variations of ≲ 1 part in 2 × 10⁷ during the past 3 or 4 months). The pulse duration is no more than ~ 0·016 s, while the period is 1#x00B7;3372795 ±0#x00B7;0000020 s (ref. 1). We understand that the other objects show similar sharp pulses at intervals of the order of 1 s, which, although not identical, strongly suggest that a new type of physical system has been discovered. Hewish et al. propose that the objects may be pulsating white dwarfs or neutron stars. Although this may prove to be correct, there are certain difficulties associated with the constancy of the observed period. We suggest an alternative explanation for the observed phenomena.