Echoes of Stars in tracking Rastall gravity

TL;DR

This paper models a star with uniform density in Rastall gravity, revealing that gravitational wave echoes can occur due to dark matter effects, offering potential observational signatures of Rastall dark energy.

Contribution

It introduces a star model in Rastall gravity with dark matter tracking dark energy, analyzing gravitational wave echoes as a novel signature.

Findings

Echo wavelets appear in axial gravitational waves due to dark matter influence.

The echo origin is linked to a potential valley near the star's surface.

Gravitational wave ringdown could reveal Rastall dark energy effects.

Abstract

We construct a star with uniform density in frame of tracking Rastall gravity, in which the density of effective dark matter tracks the density of dark energy. To demonstrate stability of the star we analyse the axial gravitational perturbations of the star. We find that echo wavelets naturally appear in the axial gravitational waves when the dark matter plays a significant role in construction of the star. We show that the physical origin of this echo roots in the potential valley near the surface of star. This effect leads to a clue to detect Rastall dark energy from the ringdown phase of gravitational wave from binary stars enriched by dark matter.