Extended Gravity Description for the GW190814 Supermassive Neutron Star

TL;DR

This paper demonstrates that the observed supermassive neutron star from GW190814 can be explained using Extended Theories of Gravity, with equations of state compatible with LIGO data, and considers the effects of rotation on its mass.

Contribution

It introduces a gravity model that accounts for the supermassive neutron star and incorporates rotation effects, expanding the understanding of such objects beyond standard models.

Findings

Neutron stars with masses over 2.6 M_sun are possible under Extended Gravity theories.

Equations of state compatible with LIGO data support the existence of such massive neutron stars.

Rotation can increase neutron star mass beyond 2.6 M_sun in these models.

Abstract

Very recently a compact object with a mass in the range $2.50\div 2.67\, M_{\odot}$ has been discovered via gravitational waves detection of a compact binary coalescence. The mass of this object makes it among the heaviest neutron star never detected or the lightest black hole ever observed. Here we show that a neutron star with this observed mass, can be consistently explained with the mass-radius relation obtained by Extended Theories of Gravity. Furthermore, equations of state, consistent with LIGO observational constraints, are adopted. We consider also the influence of rotation and show that masses of rotating neutron stars can exceed $2.6 M_\odot$ for some equations of state compatible with LIGO data.