Magnetorotational neutron star kicks

TL;DR

This paper investigates how magnetorotational supernova explosions can produce high-velocity neutron star kicks through asymmetric matter ejection, with simulations showing velocities up to 500 km/s.

Contribution

It introduces 2D magnetohydrodynamic simulations of asymmetric magnetic fields in MR supernovae, demonstrating a mechanism for neutron star kicks.

Findings

Protoneutron star kicks up to ~500 km/s observed in simulations.

Asymmetric matter ejection in jets causes the kicks.

Potential explanation for observed neutron star velocities.

Abstract

High velocity neutron stars, observed as rapidly moving radio-pulsars, are believed to gain high linear velocities -- kicks -- in aspherical supernova explosions. The mechanism of the kick formation is probably connected with anisotropic neutrino flash, and/or anisotropic matter ejection. In this paper, we investigate a neutron star kick origin in a magnetorotational (MR) supernova explosion model. The simulations have been done for a series of core collapse supernova models with initial equatorially asymmetric magnetic fields. We have realized 2D magnetohydrodynamic simulations, considering the protoneutron star kick and explosion properties in three different asymmetric magnetic field configurations. The simulations show, that in the MR supernova model protoneutron star kicks are formed with velocities up to ~500 km/s, due to asymmetric matter ejection in jets. It may explain the observed kick velocities of some neutron stars, formed in the MR supernovae explosions.