# Forecasting Interacting Vacuum-Energy Models using Gravitational Waves

## TL;DR

This paper investigates how gravitational wave data can improve constraints on interacting dark energy models, especially those involving vacuum energy and dark matter, by analyzing current cosmological datasets.

## Contribution

It introduces the use of gravitational wave data to significantly enhance parameter constraints in interacting dark energy models compared to traditional datasets.

## Key findings

- GW data improves parameter constraints by up to a factor of 4.
- Including GW data doubles the precision of combined cosmological datasets.
- Key parameters like $ heta_{MC}$ and $\sigma_8$ are most affected by GW inclusion.

## Abstract

The physics of the dark sector has remained one of the controversial areas of modern cosmology at present and hence it naturally attracts massive attention to the scientific community. With the developments of the astronomical data, the physics of the dark sector is becoming much more transparent than it was some twenty years back. The detection of gravitational waves (GWs) has now opened a cluster of possibilities in the cosmological regime. Being motivated by the detection of GWs and its possible impact on the physics of dark matter and dark energy, in this work we focus on the interacting dark energy models. Assuming the simplest possibility in which the vacuum energy with equation-of-state $w_x =-1$ is allowed to interact with the pressureless dark matter, we have extracted the constraints of the cosmological parameters. We find that the addition of the GWs data to the CMB measurements significantly improves up to a factor 4 of the parameters space, and up to a factor 2 for the full combination of current cosmological datasets, namely CMB+BAO+Pantheon+RSD+R16+CC+WL. The most affected parameters by the inclusion of the GWs are $\Omega_ch^2$, $\theta_{MC}$, $\xi$, and the derived parameters $\Omega_{m0}$, $\sigma_8$ and $H_0$.