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We suppose that a vector field perturbation causes part of the primordial curvature perturbation. The non-Gaussianity parameter fNL is then, in general, statistically anisotropic. We calculate its form and magnitude in the curvaton scenario…

Astrophysics · Physics 2009-09-02 Mindaugas Karciauskas , Konstantinos Dimopoulos , David H. Lyth

We consider possible scale-dependence of the non-linearity parameter f_NL in local and quasi-local models of non-Gaussian primordial density perturbations. In the simplest model where the primordial perturbations are a quadratic local…

Cosmology and Nongalactic Astrophysics · Physics 2010-06-15 Christian T. Byrnes , Sami Nurmi , Gianmassimo Tasinato , David Wands

We discuss models of primordial density perturbations where the non-Gaussianity is strongly scale-dependent. In particular, the non-Gaussianity may have a sharp cut-off and be very suppressed on large cosmological scales, but sizeable on…

Cosmology and Nongalactic Astrophysics · Physics 2011-02-18 Antonio Riotto , Martin S. Sloth

We investigate the halo bias in the case where the primordial curvature fluctuations, $\Phi$, are sourced from both a Gaussian random field and a Gaussian-squared field, as $\Phi({\bf x}) = \phi({\bf x}) + \psi({\bf x})^2 - <\psi({\bf…

Cosmology and Nongalactic Astrophysics · Physics 2015-05-30 Shuichiro Yokoyama

We consider cosmological inflationary models in which vector fields play some role in the generation of the primordial curvature perturbation $\zeta$. Such models are interesting because the involved vector fields naturally seed statistical…

Cosmology and Nongalactic Astrophysics · Physics 2014-11-19 Juan P. Beltran Almeida , Yeinzon Rodriguez , Cesar A. Valenzuela-Toledo

In this note we examine the derivation of scale-dependent bias due to primordial non-Gaussianity of the local type in the context of general relativity. We justify the use of the Poisson equation in general relativistic perturbation theory…

Cosmology and Nongalactic Astrophysics · Physics 2009-07-30 David Wands , Anze Slosar

We study how primordial non-Gaussianities affect the clustering of voids at large scales. We derive a formula of the bias of voids induced from the non-Gaussianities by making use of the functional integral method. In a similar way as of…

Cosmology and Nongalactic Astrophysics · Physics 2012-05-02 Toyokazu Sekiguchi , Shuichiro Yokoyama

We study the spectrum P_\zeta and bispectrum B_\zeta of the primordial curvature perturbation \zeta when the latter is generated by scalar and vector field perturbations. The tree-level and one-loop contributions from vector field…

Cosmology and Nongalactic Astrophysics · Physics 2009-11-23 Cesar A. Valenzuela-Toledo , Yeinzon Rodriguez , David H. Lyth

When dealing with observables, one needs to generalize the bias relation between the observed galaxy fluctuation field to the underlying matter distribution in a gauge-invariant way. We provide such relation at second-order in perturbation…

Cosmology and Nongalactic Astrophysics · Physics 2011-04-20 N. Bartolo , S. Matarrese , A. Riotto

Primordial non-Gaussianity encodes vital information of the physics of the early universe, particularly during the inflationary epoch. To explore the local-type primordial non-Gaussianity $f_{\mathrm{NL}}$, we study the anisotropies in…

Cosmology and Nongalactic Astrophysics · Physics 2025-03-25 Jun-Peng Li , Sai Wang , Zhi-Chao Zhao , Kazunori Kohri

We consider the generation of primordial curvature perturbation by general non-Abelian vector fields without committing to a particular group. Self-interactions of non-Abelian fields make the field perturbation non-Gaussian. We calculate…

Cosmology and Nongalactic Astrophysics · Physics 2012-01-10 Mindaugas Karciauskas

We consider inflationary models in which vector fields are responsible for part or eventually all of the primordial curvature perturbation \zeta. Such models are phenomenologically interesting since they naturally introduce anisotropies in…

Cosmology and Nongalactic Astrophysics · Physics 2013-02-05 Juan P. Beltran Almeida , Yeinzon Rodriguez , Cesar A. Valenzuela-Toledo

We study the scale dependent bias of the halo power spectrum arising from primordial non-Gaussianity. We present an analytic result of the halo bias including up to the trispectrum contributions. We find the scale dependent bias opens a new…

Cosmology and Nongalactic Astrophysics · Physics 2015-05-28 Jinn-Ouk Gong , Shuichiro Yokoyama

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 $f_{NL}$ formalism) is currently best constrained by the…

Astrophysics · Physics 2009-06-23 Marilena LoVerde , Amber Miller , Sarah Shandera , Licia Verde

Employing the perturbative treatment of gravitational clustering, we discuss possible effects of primordial non-Gaussianity on the matter power spectrum. As gravitational clustering develops, the coupling between different Fourier modes of…

Astrophysics · Physics 2009-01-08 Atsushi Taruya , Kazuya Koyama , Takahiko Matsubara

We investigate the clustering of halos in cosmological models starting with general local-type non-Gaussian primordial fluctuations. We employ multiple Gaussian fields and add local-type non-Gaussian corrections at arbitrary order to cover…

Cosmology and Nongalactic Astrophysics · Physics 2015-06-04 Takahiro Nishimichi

We revisit a possible scale-dependence of local-type primordial non-Gaussianities induced by super-horizon evolution of scalar field perturbations. We develop the formulation based on $\delta N$ formalism and derive the generalized form of…

Cosmology and Nongalactic Astrophysics · Physics 2021-12-22 Daisuke Yamauchi , Shuichiro Yokoyama , Tomo Takahashi

Local non-Gaussianity, parametrized by $f_{\rm NL}$, introduces a scale-dependent bias that is strongest at large scales, precisely where General Relativistic (GR) effects also become significant. With future data, it should be possible to…

Cosmology and Nongalactic Astrophysics · Physics 2013-05-30 Marco Bruni , Robert Crittenden , Kazuya Koyama , Roy Maartens , Cyril Pitrou , David Wands

We calculate the scale dependence of the bispectrum and trispectrum in (quasi) local models of non-Gaussian primordial density perturbations, and characterize this scale dependence in terms of new observable parameters. They can help to…

Cosmology and Nongalactic Astrophysics · Physics 2010-10-12 Christian T. Byrnes , Mischa Gerstenlauer , Sami Nurmi , Gianmassimo Tasinato , David Wands

We generalize the local model of primordial non-Gaussianity by promoting the parameter fNL to a general scale-dependent function fNL(k). We calculate the resulting bispectrum and the effect on the bias of dark matter halos, and thus the…

Cosmology and Nongalactic Astrophysics · Physics 2011-01-18 Adam Becker , Dragan Huterer , Kenji Kadota
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