Eigenfrequency of nodeless elastic vibrations locked in the crust of quaking neutron star

TL;DR

This paper develops a Newtonian solid-mechanical model for nodeless elastic vibrations in neutron star crusts, explaining certain observed X-ray oscillations as specific vibrational modes.

Contribution

It introduces a theoretical framework for classifying neutron star crust vibrations and links specific QPOs to nodeless elastic shear modes.

Findings

QPOs in SGR 1806-20 are explained by nodeless dipole torsional vibrations.

The model accounts for low-frequency QPOs previously considered unexplained.

Elastic vibrations are identified as the physical origin of certain X-ray oscillations.

Abstract

The Newtonian solid-mechanical theory of non-compressional spheroidal and torsional nodeless elastic vibrations in the homogenous crust model of a quaking neutron star is developed and applied to the modal classification of the quasi-periodic oscillations (QPOs) of X-ray luminosity in the aftermath of giant flares in SGR 1806-20 and SGR 1900+14. Particular attention is given to the low-frequency QPOs in the data for SGR 1806-20 whose physical origin has been called into question. Our calculations suggest that unspecified QPOs are due to nodeless dipole torsional and dipole spheroidal elastic shear vibrations.