The effect of realistic equations of state and general relativity on the "snowplow" model for pulsar glitches

TL;DR

This study extends the snowplow model for pulsar glitches by incorporating realistic equations of state and general relativity, successfully reproducing observed glitch features and constraining neutron star properties.

Contribution

It introduces a relativistic, realistic EoS-based extension of the snowplow model, improving the understanding of pulsar glitches and neutron star structure.

Findings

Stiffer equations of state are favored.

Vela pulsar likely has a mass less than 1.5 solar masses.

The model reproduces key glitch characteristics.

Abstract

Many pulsars are observed to "glitch", i.e. show sudden jumps in their rotational frequency $\nu$, some of which can be as large as $\Delta \nu/\nu\approx 10^{-6}-10^{-5}$ in a subset of pulsars known as giant glitchers. Recently Pizzochero (2011) has shown that an analytic model based on realistic values for the pinning forces in the crust and for the angular momentum transfer in the star can describe the average properties of giant glitches, such as the inter-glitch waiting time, the step in frequency and that in frequency derivative. In this paper we extend the model (originally developed in Newtonian gravity and for a polytropic equation of state) to realistic backgrounds obtained by integrating the relativistic equations of stellar structure and using physically motivated equations of state to describe matter in the neutron star. We find that this more detailed treatment still reproduces the main features of giant glitches in the Vela pulsar and allows us to set constraints on the equation of state. In particular we find that stiffer equations of state are favoured and that it is unlikely that the Vela pulsar has a high mass (larger than $M\approx 1.5 M_\odot$).