Effects of scale-dependent non-Gaussianity on cosmological structures
- Institute of Strings, Cosmology and Astroparticle Physics, Physics Department, Columbia University, New York, NY 10027 (United States)
- ICREA, Institut de Ciencies de l'Espai (ICE), IEEC-CSIC, Campus UAB, F. de Ciencies, Torre C5 par-2, Barcelona E-08193 (Spain)
The detection of primordial non-Gaussianity could provide a powerful means to test various inflationary scenarios. Although scale-invariant non-Gaussianity (often described by the f{sub NL} formalism) is currently best constrained by the CMB, single-field models with changing sound speed can have strongly scale-dependent non-Gaussianity. Such models could evade the CMB constraints but still have important effects at scales responsible for the formation of cosmological objects such as clusters and galaxies. We compute the effect of scale-dependent primordial non-Gaussianity on cluster number counts as a function of redshift, using a simple ansatz to model scale-dependent features. We forecast constraints on these models achievable with forthcoming datasets. We also examine consequences for the galaxy bispectrum. Our results are relevant for the Dirac-Born-Infeld model of brane inflation, where the scale dependence of the non-Gaussianity is directly related to the geometry of the extra dimensions.
- OSTI ID:
- 22137839
- Journal Information:
- Journal of Cosmology and Astroparticle Physics, Vol. 2008, Issue 04; Other Information: Country of input: International Atomic Energy Agency (IAEA); ISSN 1475-7516
- Country of Publication:
- United States
- Language:
- English
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