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

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 ∼4.5σ level. We also examine the cosmological implications of these measurements, particularly the dark energy equation of state w, its sound speed cs, and the overall curvature of the Universe. The flat ΛCDM model is a good fit to the data and, assuming this model, we find that the ISW data constrain Ωm=0.20-0.11+0.19 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 ΛCDM model with w=-1 out to redshifts z>1. © 2008 The American Physical Society.