# Gravitational wave memory in $\Lambda$CDM cosmology

## TL;DR

This paper investigates gravitational wave memory effects within a $$Lambda$\Lambda$CDM cosmology, revealing that the effect's magnitude is increased by redshift and can be influenced by lensing, even in inhomogeneous universes.

## Contribution

It extends gravitational wave memory analysis to a realistic cosmological setting, accounting for inhomogeneities and lensing effects, with results similar to flat spacetime but with enhanced magnitude.

## Key findings

- Memory effect magnitude is enhanced by redshift.
- Lensing can affect the gravitational wave memory.
- Results are similar to those in asymptotically flat spacetime.

## Abstract

We examine gravitational wave memory in the case where sources and detector are in a $\Lambda$CDM cosmology. We consider the case where the universe can be highly inhomogeneous, but the gravitatational radiation is treated in the short wavelength approximation. We find results very similar to those of gravitational wave memory in an asymptotically flat spacetime; however, the overall magnitude of the memory effect is enhanced by a redshift-dependent factor. In addition, we find the memory can be affected by lensing.