Populating the Galaxy with pulsars I: stellar & binary evolution

TL;DR

This paper introduces a comprehensive synthetic pulsar population model that evolves both isolated and binary pulsars, enabling direct comparison with observations and improving understanding of pulsar evolution and magnetic field decay.

Contribution

It presents the first integrated code for evolving pulsar populations including binary interactions, Galactic kinematics, and survey effects, advancing pulsar population synthesis.

Findings

Supports the need for magnetic field decay during accretion.

Suggests re-evaluation of typical MSP formation processes.

Reproduces observed pulsar P-Ṗ diagram and population characteristics.

Abstract

The computation of theoretical pulsar populations has been a major component of pulsar studies since the 1970s. However, the majority of pulsar population synthesis has only regarded isolated pulsar evolution. Those that have examined pulsar evolution within binary systems tend to either treat binary evolution poorly or evolve the pulsar population in an ad-hoc manner. Thus no complete and direct comparison with observations of the pulsar population within the Galactic disk has been possible to date. Described here is the first component of what will be a complete synthetic pulsar population survey code. This component is used to evolve both isolated and binary pulsars. Synthetic observational surveys can then be performed on this population for a variety of radio telescopes. The final tool used for completing this work will be a code comprised of three components: stellar/binary evolution, Galactic kinematics and survey selection effects. Results provided here support the need for further (apparent) pulsar magnetic field decay during accretion, while they conversely suggest the need for a re-evaluation of the assumed \textit{typical} MSP formation process. Results also focus on reproducing the observed $P\dot{P}$ diagram for Galactic pulsars and how this precludes short timescales for standard pulsar exponential magnetic field decay. Finally, comparisons of bulk pulsar population characteristics are made to observations displaying the predictive power of this code, while we also show that under standard binary evolutionary assumption binary pulsars may accrete much mass.