The low emission mode in PSR B0329+54

Abstract

ABSTRACT We investigate properties of the low emission mode in PSR B0329+54 based on four single-pulse observations at frequency centred at 1.54 GHz using Nanshan radio telescope in Urumqi. The low emission mode is characterized by an intensity drop in the central component below that of the other two components. Referred here as the low mode, it has an average duration of 3P0 and is observed in both abnormal and normal emission modes of the pulsar occupying 3.6 per cent of the observed pulses. We demonstrate that the properties of low modes are related to the two modes. We find that the integrated profile of low modes is unique to the two modes, and that low modes occur more frequently when the pulsar is in the normal mode. Analysis of the energy distribution for normal low modes suggests that the cause for the intensity drop in the central component is separated from the emission of the other two components. We demonstrate that the pulse emission characteristics in the normal emission mode shortly after a low-mode bears some similarities with the abnormal mode and gradually recovering to the original normal emission in about three pulsar periods. In addition, the occurrence rate for low modes in different normal modes is mostly consistent, which implies that the duration of low modes is related to a normal mode for this pulsar. Our results imply profile modes each corresponds to specific magnetospheric plama density in particular geometric configuration, and profile mode changing signifies distinct changes of both at different parts of the profile.