On the ISW-cluster cross-correlation in future surveys

TL;DR

This paper assesses the potential of future galaxy cluster surveys to detect the ISW effect through cross-correlation with CMB anisotropies, forecasting high-significance detections and improved cosmological constraints.

Contribution

It provides forecasts for the ISW-cluster cross-correlation signal-to-noise ratio using upcoming surveys like eROSITA and Euclid, and explores their cosmological parameter constraints.

Findings

ISW-cluster cross-correlation detectable at >3σ significance.

Forecasted SNRs are slightly lower than galaxy surveys but still significant.

Joint CMB and ISW-cluster analysis improves constraints on cosmological models.

Abstract

We investigate the cosmological information contained in the cross-correlation between the Integrated Sachs-Wolfe (ISW) of the Cosmic Microwave Background (CMB) anisotropy pattern and galaxy clusters from future wide surveys. Future surveys will provide cluster catalogues with a number of objects comparable with galaxy catalogues currently used for the detection of the ISW signal by cross-correlation with the CMB anisotropy pattern. By computing the angular power spectra of clusters and the corresponding cross-correlation with CMB, we perform a signal-to-noise ratio (SNR) analysis for the ISW detection as expected from the eROSITA and the Euclid space missions. We discuss the dependence of the SNR of the ISW-cluster cross-correlation on the specifications of the catalogues and on the reference cosmology. We forecast that the SNRs for ISW-cluster cross-correlation are alightly smaller compared to those which can be obtained from future galaxy surveys but the signal is expected to be detected at high significance, i.e. more than $> 3\,\sigma$. We also forecast the joint constraints on parameters of model extensions of the concordance $\Lambda$CDM cosmology by combining CMB and the ISW-cluster cross-correlation.