Restrictions to neutron star properties based on twin-peak quasi-periodic oscillations

TL;DR

This paper investigates how twin-peak quasi-periodic oscillations in neutron star binaries constrain the properties of neutron stars, revealing model-dependent relations between mass and angular momentum.

Contribution

It analyzes various QPO models to derive specific M-j relations for neutron stars, highlighting differences between high- and low-frequency sources.

Findings

Restrictions are stronger for high-frequency sources.

Different QPO models imply distinct M-j relations.

Observational data limit neutron star property ranges.

Abstract

We consider twin-peak quasi-periodic oscillations observed in the accreting low-mass neutron star binaries and explore restrictions to central compact object properties that are implied by various QPO models. For each model and each source, the consideration results in a specific relation between the compact object mass $M$ and the angular-momentum $j$ rather than in their single preferred combination. Moreover, restrictions on the models resulting from observations of the low-frequency sources are weaker than those in the case of the high-frequency sources.