Calibration of neutron star natal kick velocities to isolated pulsar observations

TL;DR

This paper introduces a physically motivated model for neutron star natal kicks based on supernova simulations, constrains its parameters using pulsar velocity data, and finds consistent kick properties across single and binary systems.

Contribution

It develops and constrains a new parameterization of neutron star natal kicks grounded in supernova physics, improving upon simple empirical models.

Findings

Best-fit kick velocity scaling factor is 520 km/s.

Fractional stochastic scatter in kicks is 0.3.

No significant difference in kick parameters between single and binary pulsars.

Abstract

Current prescriptions for supernova natal kicks in rapid binary population synthesis simulations are based on fits of simple functions to single pulsar velocity data. We explore a new parameterization of natal kicks received by neutron stars in isolated and binary systems developed by Mandel & M\"uller, which is based on 1D and 3D supernova simulations and accounts for the physical correlations between progenitor properties, remnant mass, and the kick velocity. We constrain two free parameters in this model using very long baseline interferometry velocity measurements of Galactic single pulsars. We find that the inferred values of natal kick parameters do not differ significantly between single and binary evolution scenarios. The best-fit values of these parameters are $v_{\rm ns} = 520$ km s$^{-1}$ for the scaling pre-factor for neutron star kicks, and $\sigma_{\rm ns}=0.3$ for the fractional stochastic scatter in the kick velocities.