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We consider a general initial state for inflation as the mechanism for generating scale-dependent hemispherical asymmetry. An observable scale-dependent non-Gaussianity is generated that leads to observable hemispherical asymmetry from the…

Cosmology and Nongalactic Astrophysics · Physics 2015-06-19 Hassan Firouzjahi , Jinn-Ouk Gong , Mohammad Hossein Namjoo

We place new constraints on the primordial local non-Gaussianity parameter f_NL using recent Cosmic Microwave Background anisotropy and galaxy clustering data. We model the galaxy power spectrum according to the halo model, accounting for a…

Cosmology and Nongalactic Astrophysics · Physics 2014-11-20 Francesco De Bernardis , Paolo Serra , Asantha Cooray , Alessandro Melchiorri

Using $N$-body simulations of cosmological large-scale structure formation, for the first time, we show that the anisotropic primordial non-Gaussianity (PNG) causes a scale-dependent modification, given by $1/k^2$ at small $k$ limit, in the…

Cosmology and Nongalactic Astrophysics · Physics 2021-04-21 Kazuyuki Akitsu , Toshiki Kurita , Takahiro Nishimichi , Masahiro Takada , Satoshi Tanaka

We investigate the phenomenological consequences of a modification of the initial state of a single inflationary field. While single-field inflation with the standard Bunch-Davies initial vacuum state does not generally produce a measurable…

Cosmology and Nongalactic Astrophysics · Physics 2013-05-30 Jonathan Ganc , Eiichiro Komatsu

We use hydrodynamical separate universe simulations with the IllustrisTNG model to predict the local primordial non-Gaussianity (PNG) bias parameters $b_{\phi}$ and $b_{\phi\delta}$, which enter at leading order in the galaxy power spectrum…

Cosmology and Nongalactic Astrophysics · Physics 2022-01-21 Alexandre Barreira

Non-local primordial non-Gaussianity (NLPNG) is a smoking gun of interactions in single-field inflationary models, and can be written as a combination of the equilateral and orthogonal templates. We present the first constraints on these…

Cosmology and Nongalactic Astrophysics · Physics 2022-07-20 Giovanni Cabass , Mikhail M. Ivanov , Oliver H. E. Philcox , Marko Simonović , Matias Zaldarriaga

In the pursuit of primordial non-Gaussianities, we hope to access smaller scales across larger comoving volumes. At low redshift, the search for primordial non-Gaussianities is hindered by gravitational collapse, to which we often associate…

Cosmology and Nongalactic Astrophysics · Physics 2023-02-08 Thomas Flöss , Matteo Biagetti , P. Daniel Meerburg

We investigate future constraints on primordial local-type non-Gaussianity from 21 cm angular power spectrum from minihalos. We particularly focus on the trispectrum of primordial curvature perturbations which are characterized by the…

Cosmology and Nongalactic Astrophysics · Physics 2019-02-27 Toyokazu Sekiguchi , Tomo Takahashi , Hiroyuki Tashiro , Shuichiro Yokoyama

Detecting and measuring a non-Gaussian signature of primordial origin in the density field is a major science goal of next-generation galaxy surveys. The signal will permit us to determine primordial physics processes and constrain models…

Cosmology and Nongalactic Astrophysics · Physics 2023-02-15 Adam Andrews , Jens Jasche , Guilhem Lavaux , Fabian Schmidt

The fluctuations generated by Inflation are nearly Gaussian in the simplest models, but may be non-Gaussian in more complex models, potentially leading to signatures in the late Universe. In particular, local type primordial non-Gaussianity…

Cosmology and Nongalactic Astrophysics · Physics 2025-09-03 Mponeng Kopana , Sheean Jolicoeur , Roy Maartens

Upcoming galaxy redshift surveys promise to significantly improve current limits on primordial non-Gaussianity (PNG) through measurements of 2- and 3-point correlation functions in Fourier space. However, realizing the full potential of…

Cosmology and Nongalactic Astrophysics · Physics 2021-05-19 Azadeh Moradinezhad Dizgah , Matteo Biagetti , Emiliano Sefusatti , Vincent Desjacques , Jorge Noreña

The non-Gaussianity of initial perturbations provides information on the mechanism that generated primordial density fluctuations. The expected non-Gaussianity for slow-roll inflationary models is well below the ultimate detection level…

Astrophysics · Physics 2008-11-26 Asantha Cooray

The observed distribution of galaxies has local transverse isotropy around the line-of- sight (LOS) with respect to the observer. The difference in the statistical clustering signal along and across the line-of-sight encodes important…

Cosmology and Nongalactic Astrophysics · Physics 2015-08-13 Lado Samushia , Enzo Branchini , Will Percival

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

Thanks to the rapid progress in precision cosmology in the last few years, we now have access to physical observables that may constrain the theory of inflation through the non-Gaussianity (NG) signatures in the cosmic microwave background…

Cosmology and Nongalactic Astrophysics · Physics 2013-07-19 Xinghai Zhao , Yuexing Li , Sarah Shandera , Donghui Jeong

We present a generic inference method for inflation models from observational data by the usage of higher-order statistics of the curvature perturbation on uniform density hypersurfaces. This method is based on the calculation of the…

Cosmology and Nongalactic Astrophysics · Physics 2014-06-25 Sebastian Dorn , Erandy Ramirez , Kerstin E. Kunze , Stefan Hofmann , Torsten A. Enßlin

Primordial non-Gaussianity can lead to a scale-dependent bias in the density of collapsed halos relative to the underlying matter density. The galaxy power spectrum already provides constraints on local-type primordial non-Gaussianity…

Cosmology and Nongalactic Astrophysics · Physics 2015-07-15 Matteo Tellarini , Ashley J. Ross , Gianmassimo Tasinato , David Wands

Primordial non-Gaussianity is a sensitive probe of the inflationary era, with a number of important theoretical targets living an order of magnitude beyond the reach of current CMB constraints. Maps of the large-scale structure of the…

Cosmology and Nongalactic Astrophysics · Physics 2022-09-07 Daniel Baumann , Daniel Green

If forthcoming measurements of cosmic photon polarization restrict the primordial tensor-to-scalar ratio to $r < 0.01$, small field inflation will be a principal candidate for the origin of the universe. Here we show that small multifield…

High Energy Physics - Phenomenology · Physics 2015-07-15 Joseph Bramante

A model-independent determination of the primordial power spectrum of matter density fluctuations could uniquely probe physics of the very early universe, and provide powerful constraints on inflationary models. We parametrize the…

Astrophysics · Physics 2009-10-31 Yun Wang , Grant J. Mathews