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The large-scale structure growth index $\gamma$ provides a consistency test of the standard cosmology and is a potential indicator of modified gravity. We investigate the constraints on $\gamma$ from next-generation spectroscopic surveys,…

Cosmology and Nongalactic Astrophysics · Physics 2019-12-12 José Fonseca , Jan-Albert Viljoen , Roy Maartens

We examine the nature of galaxy clustering in redshift space using a method based on an expansion of the galaxian density field in Spherical Harmonics and linear theory. We derive a compact and self-consistent expression for the distortion…

Astrophysics · Physics 2007-05-23 Karl B. Fisher

Non-gaussianity in the initial conditions of the universe is one of the most powerful mechanisms to discriminate among the competing theories of the early universe. Measurements using bispectrum of cosmic microwave background anisotropies…

Astrophysics · Physics 2009-02-23 Uros Seljak

The measurements of the statistical properties of the Cosmic Microwave Background (CMB) fluctuations enable us to probe the physics of the very early Universe especially at the epoch of inflation. A particular interest lays on the detection…

Cosmology and Nongalactic Astrophysics · Physics 2011-06-07 S. Pires , S. Plaszczynski , A. Lavabre

The power spectrum of weak lensing fluctuations has a non-Gaussian distribution due to its quadratic nature. On small scales the Central Limit Theorem acts to Gaussianize this distribution but non-Gaussianity in the signal due to…

Cosmology and Nongalactic Astrophysics · Physics 2022-06-29 Alex Hall , Andy Taylor

High-resolution N-body simulations are used to examine the power spectrum dependence of the concentration of galaxy-sized dark matter halos. It is found that dark halo concentrations depend on the amplitude of mass fluctuations as well as…

Astrophysics · Physics 2009-07-09 V. R. Eke , J. F. Navarro , M. Steinmetz

We present precise constraints on the normalization of the power spectrum of mass fluctuations in the nearby universe, sigma_8, as a function of the mean local matter density, Omega_m. Using the observed local X-ray luminosity function of…

Astrophysics · Physics 2008-11-26 S. W. Allen , R. W. Schmidt , A. C. Fabian , H. Ebeling

Within the standard paradigm, dark energy is taken as a homogeneous fluid that drives the accelerated expansion of the universe and does not contribute to the mass of collapsed objects such as galaxies and galaxy clusters. The abundance of…

Cosmology and Nongalactic Astrophysics · Physics 2017-12-07 Ronaldo C. Batista , Valerio Marra

We studied the effect of primordial non-Gaussianity with varied bispectrum shapes on the number counts of signal-to-noise peaks in wide field cosmic shear maps. The two cosmological contributions to this particular weak lensing statistic,…

Cosmology and Nongalactic Astrophysics · Physics 2015-05-27 M. Maturi , C. Fedeli , L. Moscardini

We introduce a non-Gaussian model of structure formation, and show how it produces surprising sampling effects on the estimation of the CMB power spectrum. Estimates of the average power spectrum based on small sky patches produce…

Astrophysics · Physics 2009-10-30 Charlotte Cheung , Joao Magueijo

(Abridged) Combining cosmic shear power spectra and cluster counts is powerful to improve cosmological parameter constraints and/or test inherent systematics. However they probe the same cosmic mass density field, if the two are drawn from…

Astrophysics · Physics 2009-06-23 Masahiro Takada , Sarah Bridle

We introduce a physically-motivated model of the matter power spectrum, based on the halo model and perturbation theory. This model achieves 1\% accuracy on all $k-$scales between $k=0.02h\,\mathrm{Mpc}^{-1}$ to $k=1h\,\mathrm{Mpc}^{-1}$.…

Cosmology and Nongalactic Astrophysics · Physics 2020-07-01 Oliver H. E. Philcox , David N. Spergel , Francisco Villaescusa-Navarro

The weak lensing power spectrum is a powerful tool to probe cosmological parameters. Additionally, lensing peak counts contain cosmological information beyond the power spectrum. Both of these statistics can be affected by the preferential…

Cosmology and Nongalactic Astrophysics · Physics 2014-03-07 Jia Liu , Zoltán Haiman , Lam Hui , Jan M. Kratochvil , Morgan May

We present an analytic model for the fully nonlinear power spectrum P and bispectrum Q of the cosmological mass density field. The model is based on physical properties of dark matter halos, with the three main model inputs being analytic…

Astrophysics · Physics 2009-06-16 Chung-Pei Ma , J. N. Fry

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

We present a general statistical framework for describing the effect of sample variance in the number counts of virialized objects and examine its effect on cosmological parameter estimation. Specifically, we consider effects of sample…

Astrophysics · Physics 2010-04-06 Wayne Hu , Andrey V. Kravtsov

In the standard Lambda CDM cosmological model with a Gaussian primordial density fluctuation field, the relatively low value of the mass variance parameter (sigma_8=0.74{+0.05}{-0.06}, obtained from the WMAP 3-year data) results in a…

Astrophysics · Physics 2009-06-23 S. Sadeh , Y. Rephaeli , J. Silk

The amplitude of density perturbations, for the currently-favoured LambdaCDM cosmology, is constrained using the observed properties of galaxy clusters. The catalogue used is that of Ikebe et al. (2002). The cluster temperature to mass…

Astrophysics · Physics 2009-11-07 Pedro T P Viana , Scott T Kay , Andrew R Liddle , Orrarujee Muanwong , Peter A Thomas

Weak lensing surveys are often summarized by constraints on the derived parameter ${S_8\equiv\sigma_8\sqrt{\Omega_{\rm m}/0.3}}$, obscuring the rich scale and redshift information encoded in the data, and limiting our ability to identify…

Cosmology and Nongalactic Astrophysics · Physics 2026-01-08 Cyrille Doux , Tanvi Karwal

The main goal of this work, the second in a three-paper series, is to test the impact of a methodological improvement in measuring the magnification bias signal on a sample of submillimeter galaxies and its implications for constraining…

Cosmology and Nongalactic Astrophysics · Physics 2024-05-09 Marcos M. Cueli , Joaquín González-Nuevo , Laura Bonavera , Andrea Lapi , David Crespo , José Manuel Casas
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