Giant Pulsar Glitches and the Inertia of Neutron-Star Crusts

TL;DR

This paper investigates whether the standard vortex-mediated glitch theory can explain giant pulsar glitches, considering recent findings on superfluid entrainment and dense-matter uncertainties, by calculating crustal moments of inertia with various equations of state.

Contribution

It assesses the compatibility of pulsar glitch observations with current dense-matter models and superfluid entrainment effects in neutron star crusts.

Findings

Superfluid entrainment reduces the angular momentum available for glitches.

Different dense-matter equations of state significantly affect crustal moment of inertia calculations.

Reconciliation of observations with theory depends on dense-matter properties and superfluid dynamics.

Abstract

Giant pulsar frequency glitches as detected in the emblematic Vela pulsar have long been thought to be the manifestation of a neutron superfluid permeating the inner crust of a neutron star. However, this superfluid has been recently found to be entrained by the crust, and as a consequence it does not carry enough angular momentum to explain giant glitches. The extent to which pulsar-timing observations can be reconciled with the standard vortex-mediated glitch theory is studied considering the current uncertainties on dense-matter properties. To this end, the crustal moment of inertia of glitching pulsars is calculated employing a series of different unified dense-matter equations of state.