The integrated Sachs–Wolfe effect in cosmologies with coupled dark matter and dark energy |
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Authors: | B. M. Schä fer |
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Affiliation: | Institute of Cosmology and Gravitation, University of Portsmouth, Mercantile House, Hampshire Terrace, Portsmouth PO1 2EG;Institut d'Astrophysique Spatiale, Universitéde Paris XI, bâtiment 120-121, Centre universitaire d'Orsay, 91400 Orsay CEDEX, France |
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Abstract: | The subject of this paper is the derivation of the integrated Sachs–Wolfe (iSW) effect in cosmologies with coupled dark matter and dark energy fluids. These couplings influence the iSW effect in three ways: the Hubble function assumes a different scaling, the structure growth rate shows a different time evolution and, in addition, the Poisson equation, which relates the density perturbations to fluctuations in the gravitational potential, is changed, due to the violation of the scaling ρ∝ a −3 of the matter density ρ with scalefactor a . Exemplarily, I derive the iSW spectra for a model in which dark matter decays into dark energy, investigate the influence of the dark matter decay rate and the dark energy equation of state on the iSW signal, and discuss the analogies for gravitational lensing. Quite generally, iSW measurements should reach similar accuracy in determining the dark energy equation of state parameter and the coupling constant. |
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Keywords: | methods: analytical cosmic microwave background large-scale structure of Universe |
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