Investigation of Mode Changing, Pulse Nulling and Subpulse Drifting Properties in the Asymmetric Conal Triple Radio Pulsar B2319+60

Abstract

We report on a detailed analysis of the mode changing, nulling and subpulse drifting behavior of the conal triple pulsar B2319+60 at 1.5 GHz observed with the Nanshan 25 m radio telescope. The pulsar’s profile can be interpreted as resulting from a sightline traverse which cuts across an outer cone and tangentially grazes an inner cone. About 30 per cent of nulls are found to create alternating bunches of nulls and emission in a quasi-periodic manner with an averaged fluctuation rate of about four rotation periods (P 1). The presence of two distinct drift modes (A and ABN) plus a phase-stationary non-drift emission mode (B) is confirmed, and each corresponds to a different pulse profile. The mode A is dominated by a phase modulation in the trailing component with a circulation time of around 7P 1. In addition to a 3P 1 phase modulation in the leading component, mode ABN presents an amplitude modulation in the leading and trailing components with a period of around 40P 1. The emission region and geometry remain constant during mode changing. The diversity seen in the individual pulse behavior of the pulsar B2319+60 provides a unique window into the emission physics.