Gravitational radiation from pulsar glitches

TL;DR

This paper analytically models gravitational waves generated by neutron star glitches, showing potential detectability and how wave features can reveal internal star properties and nuclear matter characteristics.

Contribution

It provides an analytical framework for gravitational wave emission from pulsar glitches, including effects of stratification and compressibility, and links wave features to star's internal physics.

Findings

Gravitational wave strain from glitches can reach detector sensitivity.

Fourier peak ratios reveal star's viscosity, compressibility, and orientation.

Transport coefficients inform the equation of state of nuclear matter.

Abstract

The nonaxisymmetric Ekman flow excited inside a neutron star following a rotational glitch is calculated analytically including stratification and compressibility. For the largest glitches, the gravitational wave strain produced by the hydrodynamic mass quadrupole moment approaches the sensitivity range of advanced long-baseline interferometers. It is shown that the viscosity, compressibility, and orientation of the star can be inferred in principle from the width and amplitude ratios of the Fourier peaks (at the spin frequency and its first harmonic) observed in the gravitational wave spectrum in the plus and cross polarizations. These transport coefficients constrain the equation of state of bulk nuclear matter, because they depend sensitively on the degree of superfluidity.