Effects of scale-dependent non-Gaussianity on cosmological structures

By M. Loverde, A. Miller, Sarah Shandera, L. Verde. 2007

276 citations recorded by the source corpus.

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 fNL 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.

Subfields: Astronomy and Astrophysics, Statistical and Nonlinear Physics

View Paper: https://www.semanticscholar.org/paper/a99696ff46c54522fb452d22f4decaa249cf3afd

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Citations in the corpus

Non-Gaussianities in single field inflation and their optimal limits from the WMAP 5-year data (2009, unknown): “The most general Lagrangian for the Goldstone boson is given by [3, 10]: Sπ = ∫ d4x √−g [ −M 2 PlḢ c2s ( π̇2 − c2s 1 a2 (∂iπ) 2 ) (8) + ḢM2Pl c2s (1− c2s)π̇ 1 a2 (∂iπ) 2 − ḢM 2 Pl c2s (1− c2s) ( 1 + 2 3 c̃3 c2s ) π̇3 −d1 4 HM3 ( 6 π̇2 + 1 a2 (∂iπ) 2 ) − (d2 + d3) 2 M2 1 a4 (∂2i π) 2 − 1 4 d1M 3…”
Cosmology and Fundamental Physics with the Euclid Satellite (2012, methodology): “, [787, 545, 954, 807, 369, 1197, 956] and references therein) and might represent a promising tool for Euclid science.”
Rapidly-Varying Speed of Sound, Scale Invariance and Non-Gaussian Signatures (2008, background): “The non-Gaussian amplitude is proportional to 1/c(2)s evaluated at horizon crossing, and therefore exhibits strong running with scale [21, 22].”
Scale-dependent bias induced by local non-Gaussianity: a comparison to N-body simulations (2008, result): “This approximation should work reasonably well for moderate values of the peak height, ν <∼4, for which the formula of LoVerde et al. (2008) matches well our data (see Fig.”
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Constraining primordial non-Gaussianity with future galaxy surveys (2011, methodology): “For this reason, in our forecasts we use the fitting formula given by PPH08 for the Gaussian mass function and multiply it by the factor (LoVerde et al. 2008) RLV ( δc σ , fNL ) ≡ [ 1 + S 3σ2 6 √ q δc ( q2 δ4c σ4 − 2q δ 2 c σ2 − 1 ) + + dS 3(σ) dlnσ2 σ 6 √ q δc ( q δ2c σ2 − 1 )] , (A10) in the…”
Primordial Non-Gaussianity and Bispectrum Measurements in the Cosmic Microwave Background and Large-Scale Structure (2010, methodology): “[137] provided an analysis of the possibility of constraining the running parameter nNG by combining current limits from the CMB on the amplitude parameter fNL at the pivot scale kp = 0.”
Primordial non-Gaussianity from the large-scale structure (2010, methodology): “It is expected that future all-sky galaxy surveys will achieve constraints of the order of ∆f loc NL ∼ 1 assuming all systematics are reasonably under control [95, 148, 149, 158, 137, 204, 205, 206].”
Halo mass function and scale-dependent bias from N-body simulations with non-Gaussian initial conditions (2008, methodology): “Most of the analytic derivations of the non-Gaussian halo mass function (e.g. Matarrese et al. 2000; LoVerde et al 2008) are based on the extended Press–Schechter model (Press & Schechter 1974; Bond et al. 1991) which, in the Gaussian case, is known to produce inaccurate estimates of halo abundance…”
Review of local non-Gaussianity from multi-field inflation (2010, background): “The scale dependence of an equilateral form of fNL has also been considered from both a theoretical and observational perspective, see for example [144–147].”