Vortex unpinning due to crustquake initiated neutron excitation and pulsar glitches

TL;DR

This paper proposes a novel mechanism where crustquakes excite superfluid neutrons, leading to vortex unpinning and pulsar glitches, applicable to various glitch sources.

Contribution

It introduces a new unpinning mechanism driven by neutron excitation from crustquakes, expanding understanding of pulsar glitch origins.

Findings

Glitch sizes for Crab and Vela pulsars are consistent with the proposed mechanism.

Neutron scattering can significantly reduce vortex pinning forces.

The mechanism is applicable beyond crustquakes to other excitation sources.

Abstract

Pulsars undergoing crustquake release strain energy, which can be absorbed in a small region inside the inner crust of the star and excite the free superfluid neutrons therein. The scattering of these neutrons with the surrounding pinned vortices may unpin a large number of vortices and effectively reduce the pinning force on vortex lines. Such unpinning by neutron scattering can produce glitches for Crab like pulsars and Vela pulsar of size in the range $\sim 10^{-8} - 10^{-7}$, and $\sim 10^{-9} - 10^{-8}$, respectively. Although we discuss here the crustquake initiated excitation, the proposal is very generic and equally applicable for any other sources, which can excite the free superfluid neutrons, or can be responsible for superfluid - normal phase transition of neutron superfluid in the inner crust of a pulsar.