Repulsion of fallback matter due to central energy source in supernova

TL;DR

This paper introduces new self-similar solutions to describe how fallback matter in supernovae is repelled by central energy sources, influencing neutron star diversity.

Contribution

It presents novel self-similar solutions for fallback matter dynamics, revealing conditions for maximum accretion rates and implications for neutron star formation.

Findings

Existence of a maximum accretion rate for adiabatic index ≤ 4/3

Arbitrarily large accretion rates possible with small energy deposition regions

Fallback accretion rates could explain the diversity of young neutron stars

Abstract

The flow of fallback matter being shocked and repelled back by an energy deposition from a central object is discussed by using newly found self-similar solutions. We show that there exists a maximum mass accretion rate if the adiabatic index of the flow is less than or equal to 4/3. Otherwise we can find a solution with an arbitrarily large accretion rate by appropriately shrinking the energy deposition region. Applying the self-similar solution to supernova fallback, we discuss how the fate of newborn pulsars or magnetars depends on the fallback accretion and their spin-down power. Combining the condition for the fallback accretion to bury the surface magnetic field into the crust, we argue that supernova fallback with a rate of dM_{fb}/dt ~ 10^{-(4-6)} M_sun /s could be the main origin of the diversity of Galactic young neutron stars, i.e., rotation-powered pulsars, magnetars, and central compact objects.