Intensity Dependence of the PSR 0329+54 Pulse Profile

Abstract

Following the analysis by Krishnamohan and Downs (1983) of the Vela pulsar, we have investigated the behavior of the core and outrider components of PSR 0329+54 by calculating pulse profiles at different pulse intensities. VLA observations of individual pulses from PSR 0329+54 at 1415 MHz were used in our analysis. Our investigation reveals the following dependencies upon increasing core peak intensity: (i) earlier core arrival times, (ii) decreasing separation of the left outrider relative to the core, (iii) increasing separation of the right outrider relative to the core, (iv) decreasing outrider-to-core peak intensity ratios, and (v) essentially constant core width. To explain these dependencies, we propose a simple model in which the location of the core centroid is altered near the neutron star surface. The model and data are consistent with the mode-switching signatures and magnetospheric absorption features known to exist in this pulsar.