Journal Article

Mixed three-point correlation functions of the non-linear integrated Sachs–Wolfe effect and their detectability

B. M. Schäfer

in Monthly Notices of the Royal Astronomical Society

Published on behalf of The Royal Astronomical Society

Volume 388, issue 3, pages 1394-1402
Published in print August 2008 | ISSN: 0035-8711
Published online July 2008 | e-ISSN: 1365-2966 | DOI: http://dx.doi.org/10.1111/j.1365-2966.2008.13526.x
Mixed three-point correlation functions of the non-linear integrated Sachs–Wolfe effect and their detectability

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In this paper, I investigate the family of mixed three-point correlation functions 〈τqγ3−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 ℓ= 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.

Keywords: methods: analytical; cosmic microwave background; large-scale structure of Universe

Journal Article.  5479 words.  Illustrated.

Subjects: Astronomy and Astrophysics

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