Combined analysis of the integrated Sachs-Wolfe effect and cosmological implications

TL;DR

This paper measures the integrated Sachs-Wolfe effect by cross-correlating galaxy data with CMB maps, detecting the signal at 4.5 sigma, and explores its implications for dark energy and universe curvature.

Contribution

It provides a comprehensive measurement of the ISW effect using all relevant galaxy data and analyzes its cosmological implications within the flat LCDM model.

Findings

ISW signal detected at ~4.5 sigma level

Constraints on matter density Omega_m consistent with LCDM

Results support a flat universe with dark energy equation of state w = -1

Abstract

We present a global measurement of the integrated Sachs-Wolfe (ISW) effect obtained by cross-correlating all relevant large scale galaxy data sets with the cosmic microwave background radiation map provided by the Wilkinson Microwave Anisotropy Probe. With these measurements, the overall ISW signal is detected at the ~ 4.5 sigma level. We also examine the cosmological implications of these measurements, particularly the dark energy equation of state w, its sound speed, and the overall curvature of the Universe. The flat LCDM model is a good fit to the data and, assuming this model, we find that the ISW data constrain Omega_m = 0.20 +0.19 -0.11 at the 95% confidence level. When we combine our ISW results with the latest baryon oscillation and supernovae measurements, we find that the result is still consistent with a flat LCDM model with w = -1 out to redshifts z > 1.