Detection of the ISW and SZ effects from the CMB-Galaxy correlation

TL;DR

This study detects correlations between CMB and galaxy distributions, confirming the ISW and SZ effects, and constrains dark energy parameters using cross-correlation analysis of WMAP and SDSS data.

Contribution

It provides the first combined detection of ISW and SZ effects from multiple galaxy samples and estimates galaxy bias to constrain dark energy parameters.

Findings

Significant detection of CMB-galaxy correlation for multiple samples.

Consistent support for a dark-energy dominated universe with LambdaD rac{0.69}{0.86}.

Estimated Compton parameter yA010^{-6}.

Abstract

We present a cross-correlation analysis of the WMAP cosmic microwave background (CMB) temperature anisotropies and the SDSS galaxy density fluctuations. We find significant detections of the angular CMB-galaxy correlation for both the flux limited galaxy sample (z~0.3) and the high redshift (z ~ 0.5) color selected sample. The signal is compatible with that expected from the integrated Sachs-Wolfe (ISW) effect at large angles (\theta > 3deg) and the Sunyaev-Zeldovich (SZ) effect at small scales (\theta < 1 deg). The detected correlation at low-z is in good agreement with a previous analysis using the APM survey (z~0.15). The combined analysis of all 3 samples yields a total significance better than 3 sigma for ISW and about 2.7 \sigma for SZ, with a Compton parameter y~10^(-6). For a given flat LCDM model, the ISW effect depends both on the value of \Omega_\Lambda and the galaxy bias b. To break this degeneracy, we estimate the bias using the ratio between the galaxy and mass auto-correlation functions in each sample. With our bias estimation, all samples consistently favor a best fit dark-energy dominated model: \Omega_\Lambda ~ 0.8, with a 2 \sigma error \Omega_\Lambda=0.69-0.86.