Abstract
The integrated Sachs-Wolfe (ISW) effect predicts additional anisotropies in the cosmic microwave background (CMB) due to time variation of the gravitational potential when the expansion of the Universe is not matter dominated. The ISW effect is therefore expected in the early Universe, due to the presence of relativistic particles at recombination, and in the late Universe, when dark energy starts to dominate the expansion. Deviations from the standard picture can be parametrized by and , which rescale the overall amplitude of the early and late ISW effects. Analyzing the most recent CMB temperature spectra from the Planck 2015 release, we detect the presence of the early ISW at high significance with at 68% C.L. and an upper limit for the late ISW of at 95% C.L. The inclusion of the recent polarization data from the Planck experiment results in at 68% C.L., in better agreement with the value of a standard cosmology. When considering the recent detections of the late ISW coming from correlations between CMB temperature anisotropies and weak lensing, a value of is predicted at 68% C.L., showing evidence. We discuss the stability of our result in the case of an extra relativistic energy component parametrized by the effective neutrino number and of a CMB lensing amplitude .
1 More- Received 29 July 2015
DOI:https://doi.org/10.1103/PhysRevD.92.063534
© 2015 American Physical Society