# Entrainment factor on individual glitch fractional moment of inertia

## TL;DR

This paper investigates how crustal entrainment affects the fractional moment of inertia in neutron star glitches, revealing some glitches may require a larger superfluid component than previously estimated.

## Contribution

It introduces a calculation of the fractional moment of inertia considering entrainment effects, providing new insights into the superfluid's role in pulsar glitches.

## Key findings

- Entrainment reduces the effective moment of inertia involved in glitches.
- Some glitches imply a superfluid component larger than 7-10% of the star's moment of inertia.
- The effective moment of inertia is primarily that of entrained neutrons.

## Abstract

The superfluid in the inner crust of neutron star is assumed to be the reservoir of momentum released in pulsar glitch. Recently, due to crustal entrainment, it is debatable whether the magnitude of the inner crust is sufficient to contain superfluid responsible for large glitches. This paper calculates the fractional moment of inertia (FMI)(i.e. the ratio of the inner crust superfluid moment of inertia to that of the coupled components) associated with individual glitches. It is shown that the effective moment of inertia associated with the transferred momentum is that of the entrained neutrons. The FMI for glitches in three pulsars, which exhibit the signature of exhausting their momentum reservoir were calculated and scaled with entrainment factor. Some of the glitches require inner crust superfluid with moment of inertia larger than the current suggested values of 7-10 % of the stellar moment of inertia.