Cosmological Bound from the Neutron Star Merger GW170817 in scalar-tensor and $F(R)$ gravity theories

TL;DR

This paper investigates how gravitational waves from neutron star mergers behave in scalar-tensor and $F(R)$ gravity theories, highlighting potential observable phase differences from standard cosmology.

Contribution

It analyzes the phase evolution of gravitational waves in modified gravity models, providing predictions for future observational tests.

Findings

Propagation speed remains unchanged from light speed.

Phase of gravitational waves differs from $ m ext{ extLambda CDM}$ model.

Potential detectability of phase differences in future observations.

Abstract

We consider the evolution of cosmological gravitational waves in scalar-tensor theory and $F(R)$ gravity theory as typical models of the modified gravity. Although the propagation speed is not changed from the speed of light, the propagation phase changes when we compare the propagation in these modified gravity theories with the propagation in the $\Lambda$CDM model. The phase change might be detected in future observations.