Mixed three-point correlation functions of the non-linear integrated Sachs–Wolfe effect and their detectability |
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| Authors: | B M Schäfer |
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| Institution: | Institute of Cosmology and Gravitation, University of Portsmouth, Mercantile House, Hampshire Terrace, Portsmouth PO12EG;Institut d'Astrophysique Spatiale, Universitéde Paris XI, bâtiment 120-121, Centre universitaire d'Orsay, 91400 Orsay CEDEX, France |
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| Abstract: | In this paper, I investigate the family of mixed three-point correlation functions 〈τ q γ3? q 〉, q = 0, 1, 2 , between the integrated Sachs–Wolfe (iSW) temperature perturbation τ and the galaxy overdensity γ as a tool for detecting the gravitational interaction of cosmic microwave background (CMB) photons with the potentials of non-linearly evolving cosmological structures. Both the iSW-effect and the galaxy overdensity are derived in hyperextended perturbation theory to second order and I emphasize the different parameter sensitivities of the linear and non-linear iSW-effect. I examine the configuration dependence of the relevant bispectra, quantify their sensitivities and discuss their degeneracies with respect to the cosmological parameters Ωm, σ8, h and the dark energy equation of state parameter w . I give detection significances for combining Planck CMB data and galaxy sample of a survey like Dark UNiverse Explorer (DUNE) by using a quadratic approximation for the likelihood with Λ cold dark matter (ΛCDM) as the fiducial cosmology: the combination of Planck with DUNE should be able to reach a cumulative signal-to-noise ratio of ?0.6 for the bispectrum 〈τγ2〉 up to ?= 2000, which is too weak to be detected. The most important noise source is the primary CMB fluctuations as the Poisson noise in the galaxy number density is almost negligible for a survey like DUNE. |
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| Keywords: | methods: analytical cosmic microwave background large-scale structure of Universe |
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