On the propagation of gravitational waves in strong magnetic fields

TL;DR

This paper investigates how strong magnetic fields in the cosmos, such as those in galaxies, can significantly affect the way gravitational waves travel, highlighting differences between general relativity and scalar-tensor theories.

Contribution

It provides a detailed analysis of gravitational wave propagation in magnetic fields and estimates the effect in a specific galaxy, expanding understanding of medium effects on gravitational waves.

Findings

Magnetic fields can influence gravitational wave propagation significantly.

Differences between general relativity and scalar-tensor theory are evident in thermal radiation.

Estimated effects are relevant for spiral galaxy NGC 6946.

Abstract

The propagation of gravitational waves is explored in the cosmological context. It is explicitly demonstrated that the propagation of gravitational waves could be influenced by the medium. It is shown that in the thermal radiation, the propagation of gravitational waves in general relativity is different from that in the scalar-tensor theory. The propagation of gravitational waves is investigated in the uniform magnetic field. As a result, it is found that cosmic magnetic fields could influence on the propagation of gravitational waves to non-negligible extent. The corresponding estimation for the spiral galaxy NGC 6946 effect is made.