Periodic modulation in pulse arrival times from young pulsars: a renewed case for neutron star precession

TL;DR

This study detects periodic timing variations in young pulsars, suggesting intrinsic neutron star precession as the cause, rather than planetary companions, based on statistical analysis and simulations.

Contribution

It provides evidence for neutron star precession as the origin of observed pulse timing modulations in young pulsars, challenging planetary companion explanations.

Findings

Seven pulsars show significant periodic modulation in pulse arrival times.

Modulation periods range from 0.5 to 1.5 years.

Precession likely causes the observed magnetospheric switching.

Abstract

In a search for periodic variation in the arrival times of pulses from 151 young, energetic pulsars, we have identified seven cases of modulation consistent with one or two harmonics of a single fundamental with time-scale 0.5-1.5 yr. We use simulations to show that these modulations are statistically significant and of high quality (sinusoidal) even when contaminated by the strong stochastic timing noise common to young pulsars. Although planetary companions could induce such modulation, the large implied masses and 2:1 mean motion resonances challenge such an explanation. Instead, the modulation is likely to be intrinsic to the pulsar, arising from quasi-periodic switching between stable magnetospheric states, and we propose that precession of the neutron star may regulate this switching.