Structures of the Vela pulsar and the glitch crisis from the Brueckner theory

TL;DR

This paper models the Vela pulsar's internal structure using microscopic Brueckner-Hartree-Fock calculations and examines the glitch crisis, suggesting core neutrons may be needed to explain large observed glitches.

Contribution

It provides the first microscopic analysis of the glitch crisis by calculating the crustal moment of inertia and comparing it with observational data.

Findings

Crustal moment of inertia constraints challenge the glitch crisis.

Superfluid neutrons in the crust are insufficient to explain large glitches.

Core neutrons may be necessary for large glitch phenomena.

Abstract

Detailed structures of the Vela pulsar (PSR B0833-45, with a period of $89.33$ milliseconds) are predicted by adopting a recently-constructed unified treatment of all parts of neutron stars: the outer crust, the inner crust and the core based on modern microscopic Brueckner-Hartree-Fock calculations. To take the pulsar mass ranging from $1.0M_{\odot}$ to $2.0M_{\odot}$, we calculate the central density, the core/crust radii, the core/crust mass, the core/crustal thickness, the moment of inertia, and the crustal moment of inertia. Among them, the crustal moment of inertia could be effectively constrained from the accumulated glitch observations, which has been a great debate recently, known as "glitch crisis". Namely, superfluid neutrons contained in the inner crust, which are regarded as the origin of the glitch in the standard two-component model, could be largely entrained in the nuclei lattices, then there may not be enough superfluid neutrons ($\sim 4/5$ less than the previous value) to trigger the large glitches ($\Delta \nu/\nu_0 \sim 10^{-6}$) in the Vela pulsar. We then provide the first analysis of the crisis based on the microscopic basis, by confronting the glitch observations with the theoretical calculations for the crustal moment of inertia. We find that despite some recent opposition to the crisis argument, the glitch crisis is still present, which means that besides the crust superfluid neutrons, core neutrons might be necessary for explaining the large glitches of the Vela pulsar.