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 $\ensuremath{\sim}4.5\ensuremath{\sigma}$ level. We also examine the cosmological implications of these measurements, particularly the dark energy equation of state $w$, its sound speed ${c}_{s}$, and the overall curvature of the Universe. The flat $\ensuremath{\Lambda}\mathrm{CDM}$ model is a good fit to the data and, assuming this model, we find that the ISW data constrain ${\ensuremath{\Omega}}_{m}={0.20}_{\ensuremath{-}0.11}^{+0.19}$ 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 $\ensuremath{\Lambda}\mathrm{CDM}$ model with $w=\ensuremath{-}1$ out to redshifts $z>1$.