Cosmic microwave background bispectrum on small angular scales

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dc.creatorPitrou, Cyril
dc.creatorUzan, Jean-Philippe
dc.creatorBernardeau, Francis
dc.date2008-07-02
dc.date2008-09-18
dc.date.accessioned2026-07-07T12:44:40Z
dc.date.available2026-07-07T12:44:40Z
dc.descriptionThis article investigates the non-linear evolution of cosmological perturbations on sub-Hubble scales in order to evaluate the unavoidable deviations from Gaussianity that arise from the non-linear dynamics. It shows that the dominant contribution to modes coupling in the cosmic microwave background temperature anisotropies on small angular scales is driven by the sub-Hubble non-linear evolution of the dark matter component. The perturbation equations, involving in particular the first moments of the Boltzmann equation for the photons, are integrated up to second order in perturbations. An analytical analysis of the solutions gives a physical understanding of the result as well as an estimation of its order of magnitude. This allows to quantify the expected deviation from Gaussianity of the cosmic microwave background temperature anisotropy and, in particular, to compute its bispectrum on small angular scales. Restricting to equilateral configurations, we show that the non-linear evolution accounts for a contribution that would be equivalent to a constant primordial non-Gaussianity of order fNL~25 on scales ranging approximately from l~1000 to l~3000.
dc.description21 pages, replaced to match published version
dc.identifierhttps://arxiv.org/abs/0807.0341
dc.identifierhttp://arxiv.org/abs/0807.0341
dc.identifierPhys.Rev.D78:063526,2008
dc.identifierdoi:10.1103/PhysRevD.78.063526
dc.identifier.urihttp://salesiana.dossiersoluciones.com/handle/123456789/220850
dc.subjectAstrophysics
dc.titleCosmic microwave background bispectrum on small angular scales
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