Modeling large glitches with core superfluidity in a Hybrid star

TL;DR

This paper proposes a hybrid star model with core superfluidity and vortex pinning in quark pasta structures to explain large pulsar glitches, aligning theoretical predictions with observed glitch magnitudes.

Contribution

It introduces a hybrid star model with vortex pinning in the core's quark pasta structures, explaining large pulsar glitches previously unaccounted for.

Findings

Core contribution yields glitch sizes of order 10^{-6}

Vortex pinning in quark pasta structures explains giant glitches

Model aligns with observed Vela-like pulsar glitches

Abstract

Many pulsars exhibit a peculiar behaviour in their pulse profile of a sudden increase in their rotational period, which is popularly known as a pulsar glitch. Some of them show giant glitches with relative amplitude $\Delta\Omega/\Omega \sim 10^{-6}-10^{-5}$. With the model of pinned neutron vortices inside the neutron star (NS) crust, this large glitch cannot be explained so far. However, the increasing evidence of massive pulsars indicates the appearance of exotic degrees of freedom in the inner core of the pulsars. Given this, we consider the pulsar as a hybrid star (HS). This model opens up the possibility of vortex-pinning inside the core. Under the Gibbs equilibrium conditions, it is possible for hadrons and the quark phase to coexist. Due to the global charge neutrality condition, quark pasta structures are formed in the background of hadronic matter. We consider these pasta structures as pinning sites of superfluid vortices. We show that considering the core contribution, our calculations come to be of the order of $\Delta\Omega/\Omega \sim 10^{-6}$, which is close to the observations shown by the Vela-like pulsars.