Cosmic strings and their induced non-Gaussianities in the cosmic microwave background
May, 2010Citations per year
Abstract: (arXiv)
Motivated by the fact that cosmological perturbations of inflationary quantum origin were born Gaussian, the search for non-Gaussianities in the cosmic microwave background (CMB) anisotropies is considered as the privileged probe of non-linear physics in the early universe. Cosmic strings are active sources of gravitational perturbations and incessantly produce non-Gaussian distortions in the CMB. Even if, on the currently observed angular scales, they can only contribute a small fraction of the CMB angular power spectrum, cosmic strings could actually be the main source of its non-Gaussianities. In this article, after having reviewed the basic cosmological properties of a string network, we present the signatures Nambu-Goto cosmic strings would induce in various observables ranging from the one-point function of the temperature anisotropies to the bispectrum and trispectrum. It is shown that string imprints are significantly different than those expected from the primordial type of non-Gaussianity and could therefore be easily distinguished.Note:
- 50 pages, 20 figures, uses iopart. Misprints corrected, references added, matches published version
- 98.70.Vc
- 98.80.Cq
- perturbation: gravitation
- temperature: anisotropy
- power spectrum: angular dependence
- non-Gaussianity
- cosmic background radiation: fluctuation
- cosmic string: network
- error: statistical
- inflation
References(190)
Figures(29)