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We study evolution of perturbations in dark matter and dark energy for spherical collapse. We study Tachyon models of dark energy using the approach outlined in Rajvanshi and Bagla (2018). We work with models that are allowed by current…

Cosmology and Nongalactic Astrophysics · Physics 2021-04-13 Manvendra Pratap Rajvanshi , J. S. Bagla

The radial mass distribution of dark matter haloes is investigated within the framework of the spherical infall model. We present a new formulation of spherical collapse including non-radial motions, and compare the analytical profiles with…

Astrophysics · Physics 2009-11-10 Y. Ascasibar , G. Yepes , S. Gottloeber , V. Mueller

In this article, we review a series of recent theoretical results regarding a conventional approach to the dark energy (DE) concept. This approach is distinguished among others for its simplicity and its physical relevance. By compromising…

Cosmology and Nongalactic Astrophysics · Physics 2016-04-20 Kostas Kleidis , Nikolaos K. Spyrou

We present a first principle approach to obtain analytical predictions for spherically-averaged cosmic densities in the mildly non-linear regime that go well beyond what is usually achieved by standard perturbation theory. A large deviation…

Cosmology and Nongalactic Astrophysics · Physics 2016-05-25 Cora Uhlemann , Sandrine Codis , Christophe Pichon , Francis Bernardeau , Paulo Reimberg

In this paper I consider the nonlinear evolution of a rare density fluctuation in a random density field with Gaussian fluctuations, and I rigorously show that it follows the spherical collapse dynamics applied to its mean initial profile.…

Astrophysics · Physics 2009-10-22 F. Bernardeau

Spherical collapse predicts that a single value of the turnaround density (average matter density within the scale on which a structure detaches from the Hubble flow) characterizes all cosmic structures at the same redshift. It has been…

Cosmology and Nongalactic Astrophysics · Physics 2020-07-01 Vasiliki Pavlidou , Giorgos Korkidis , Theodore Tomaras , Dimitrios Tanoglidis

In the excursion set approach to structure formation initially spherical regions of the linear density field collapse to form haloes of mass $M$ at redshift $z_{\rm id}$ if their linearly extrapolated density contrast, averaged on that…

Cosmology and Nongalactic Astrophysics · Physics 2014-11-07 Aaron D. Ludlow , Mikolaj Borzyszkowski , Cristiano Porciani

We extend the analysis of Pace et al., JCAP, 2019, 060, by considering the virialization process in the extended spherical collapse model for clustering dark-energy models, i.e., accounting for dark-energy fluctuations. Differently from the…

Cosmology and Nongalactic Astrophysics · Physics 2022-04-07 Francesco Pace , Carlo Schimd

We study the imprints on the formation of cosmic structures of a particular class of dark energy parameterizations dubbed PADE parameterization. Here we investigate how dark energy can affect the growth of large scale structures of the…

General Relativity and Quantum Cosmology · Physics 2019-05-07 Mehdi Rezaei

{abridged} We study the imprints on the formation and evolution of cosmic structures of dynamical dark energy models, characterized by an oscillating equation of state. The redshift evolution of the equation of state parameter w(z) for dark…

Cosmology and Nongalactic Astrophysics · Physics 2015-03-19 F. Pace , C. Fedeli , L. Moscardini , M. Bartelmann

The expansion rate of the Universe changes with time, initially slowing (decelerating) when the universe was matter dominated, because of the mutual gravitational attraction of all the matter in it, and more recently speeding up…

Cosmology and Nongalactic Astrophysics · Physics 2013-09-17 Muhammad Omer Farooq

In this first paper we discuss the linear theory and the background evolution of a new class of models we dub SCDEW: Strongly Coupled DE, plus WDM. In these models, WDM dominates today's matter density; like baryons, WDM is uncoupled. Dark…

Cosmology and Nongalactic Astrophysics · Physics 2015-10-09 Silvio A. Bonometto , Roberto Mainini , Andrea V. Macciò

We examine the linear density contrast at collapse time, $\delta_c$ for large-scale structure in dynamical dark energy cosmologies, including models with early dark energy. Contrary to previous results, we find that as long as dark energy…

Astrophysics · Physics 2010-03-19 Matthew J. Francis , Geraint F. Lewis , Eric V. Linder

We report the findings of new exact analytical solutions to the cosmological fluid equations, namely for the case where the initial conditions are perturbatively close to a spherical top-hat profile. To do so we enable a fluid description…

Cosmology and Nongalactic Astrophysics · Physics 2019-02-28 Cornelius Rampf

We present the nonlinear growth of bound cosmological structures using the spherical collapse approach in the shift-symmetric Galileon theories. In particular, we focus on the class of models belonging to the Kinetic Gravity Braiding by…

Cosmology and Nongalactic Astrophysics · Physics 2024-01-09 Inês S. Albuquerque , Noemi Frusciante , Francesco Pace , Carlo Schimd

Cosmological Perturbation Theory (PT) is a useful tool to study the cumulants of the density and velocity fields in the large scale structure of the Universe. In Papers I & II of this series we saw that the Spherical Collapse (SC) model…

Astrophysics · Physics 2009-10-30 P. Fosalba , E. Gaztanaga

While there is plentiful evidence in all fronts of experimental cosmology for the existence of a non-vanishing dark energy (DE) density \rho_D in the Universe, we are still far away from having a fundamental understanding of its ultimate…

Astrophysics · Physics 2011-07-19 Javier Grande , Ana Pelinson , Joan Sola

In this work, we study the collapse dynamics of an inhomogeneous spherically symmetric star made of dark matter (DM) and dark energy (DE). The dark matter is taken in the form of a dust cloud while anisotropic fluid is chosen as the…

General Relativity and Quantum Cosmology · Physics 2014-11-17 Subenoy Chakraborty , Tanwi Bandyopadhyay

Recently, a supersymmetric model of dark energy coupled to cold dark matter, the supersymmetron, has been proposed. In the absence of cold dark matter, the supersymmetron field converges to a supersymmetric minimum with a vanishing…

Cosmology and Nongalactic Astrophysics · Physics 2013-05-30 Philippe Brax , Anne-Christine Davis , Hans A. Winther

In this paper, we derive some new invariant solutions of dark energy models in cylindrically symmetric space-time. To quantify the deviation of pressure from isotropy, we introduce three different time dependent skewness parameters along…

General Relativity and Quantum Cosmology · Physics 2014-09-10 Anil Kumar Yadav , Ahmad T Ali