The Integrated Sachs-Wolfe Effect in Time Varying Vacuum Model

TL;DR

This paper calculates the ISW effect power spectrum in a time varying vacuum model, showing how matter production influences the effect and discussing the observational challenges in distinguishing it from the standard model.

Contribution

It introduces a detailed calculation of the ISW effect in a time varying vacuum cosmology, highlighting the impact of matter production on the effect's sources.

Findings

The ISW effect is affected by the evolution of H(a), Ω_m(a), and D_+(a).

Differences between the models are reduced due to integration over cosmic history.

High-redshift galaxy observations are needed to distinguish models.

Abstract

The integrated Sachs-Wolfe (ISW) effect is an important implication for dark energy. In this paper, we have calculated the power spectrum of the ISW effect in the time varying vacuum cosmological model, where the model parameter $\beta=4.407$ is obtained by the observational constraint of the growth rate. It's found that the source of the ISW effect is not only affected by the different evolutions of the Hubble function $H(a)$ and the dimensionless matter density $\Omega_m(a)$, but also by the different growth function $D_+(a)$, all of which are changed due to the presence of matter production term in the time varying vacuum model. However, the difference of the ISW effect in $\Lambda(t)\textmd{CDM}$ model and $\Lambda \textmd{CDM}$ model is lessened to a certain extent due to the integration from the time of last scattering to the present. It's implied that the observations of the galaxies with high redshift are required to distinguish the two models.