Crustal Entrainment and Pulsar Glitches

TL;DR

This paper investigates how non-dissipative entrainment effects in neutron star crusts limit angular momentum transfer during pulsar glitches, revealing the need for additional angular momentum reservoirs to explain observed Vela pulsar glitches.

Contribution

It demonstrates that crustal entrainment effects significantly constrain the angular momentum transfer, challenging previous models and indicating the necessity of extra reservoirs.

Findings

Entrainment effects limit maximum angular momentum transfer.

Vela pulsar glitches require additional angular momentum sources.

Crustal superfluid alone cannot explain observed glitches.

Abstract

Large pulsar frequency glitches are generally interpreted as sudden transfers of angular momentum between the neutron superfluid permeating the inner crust and the rest of the star. Despite the absence of viscous drag, the neutron superfluid is strongly coupled to the crust due to non-dissipative entrainment effects. These effects are shown to severely limit the maximum amount of angular momentum that can possibly be transferred during glitches. In particular, it is found that the glitches observed in the Vela pulsar require an additional reservoir of angular momentum.