Speaker
Description
Rapidly moving neutron stars 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 during the explosion. In this paper, we investigate a neutron star's kick origin due to a recoil effect in a magnetorotational (MR) supernova explosion model. The simulations have been done for a series of core collapse supernova models of a massive star with rotation and initial equatorially asymmetric magnetic fields. We have conducted 2D MHD simulations, considering the kick of a protoneutron star and explosion properties in three different asymmetric magnetic field configurations, namely in presence of multipoles composition in the core, an offset dipole field, as well as a superposition of dipolar and toroidal fields. The simulations show that in the MR supernova model protoneutron star kicks are formed with velocities up to ~500 km/s during ~1 second after the core bounce, due to asymmetric matter ejection in jet-like outflows, which may explain the observed kick velocities. Additionally we have performed a study of the dependence of the recoil effect in this scenario on a presupernova mass.
