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We study the spherical, top-hat collapse model for a mixed dark matter model including cold dark matter (CDM) and massive neutrinos of mass scales ranging from m_nu= 0.05 to a few 0.1eV, the range of lower- and upper-bounds implied from the…

Cosmology and Nongalactic Astrophysics · Physics 2013-05-30 Kiyotomo Ichiki , Masahiro Takada

In this work we discuss a general approach for the dissipative dark matter considering a nonextensive bulk viscosity and taking into account the role of generalized Friedmann equations. This generalized $\Lambda$CDM model encompasses a flat…

Cosmology and Nongalactic Astrophysics · Physics 2018-10-19 W. J. C. da Silva , H. S. Gimenes , R. Silva

We study the gravitational clustering of spherically symmetric overdensities and the statistics of the resulting dark matter halos in the "symmetron model", in which a new long range force is mediated by a $Z_2$ symmetric scalar field.…

Cosmology and Nongalactic Astrophysics · Physics 2015-06-17 Laura Taddei , Riccardo Catena , Massimo Pietroni

The nonlinear collapse for viscous generalized Chaplygin gas Model (VGCG) was analyzed in the framework of spherical top-hat collapse. As the VGCG and baryons are essential to form the large scale structure, we focused on their nonlinear…

Cosmology and Nongalactic Astrophysics · Physics 2014-07-21 Wei Li , Lixin Xu

Recently a modified version of Rastall theory of gravity has been introduced in which a varying coupling parameter could act as dark energy (DE) and thus, it can be held responsible for the current accelerated expansion of the Universe.…

General Physics · Physics 2020-11-20 A. H. Ziaie , H. Moradpour , H. Shabani

The Generalized Uncertainty Principle (GUP) stands out as a nearly ubiquitous feature in quantum gravity modeling, predicting the emergence of a minimum length at the Planck scale. Recently, it has been shown to modify the area-law scaling…

General Relativity and Quantum Cosmology · Physics 2025-02-17 Giuseppe Gaetano Luciano , Yassine Sekhmani

The present work deals with the spherical collapse of matter overdensity for two reconstructed dark energy models. One of the models is reconstructed from parametrization of effective or total equation of state of energy components in the…

Cosmology and Nongalactic Astrophysics · Physics 2025-03-18 Ankan Mukherjee

We investigate the virialization of cosmic structures in the framework of flat FLRW cosmological models, in which the vacuum energy density evolves with time. In particular, our analysis focuses on the study of spherical matter…

Cosmology and Nongalactic Astrophysics · Physics 2014-11-21 S. Basilakos , M. Plionis , J. Sola

In previous work [L. Blanchet and A. Le Tiec, Phys. Rev. D 80, 023524 (2009)], motivated by the phenomenology of dark matter at galactic scales, a model of dipolar dark matter (DDM) was introduced. At linear order in cosmological…

General Relativity and Quantum Cosmology · Physics 2013-08-26 Luc Blanchet , David Langlois , Alexandre Le Tiec , Sylvain Marsat

Unified dark matter models are appealing in that they describe the dark sector in terms of a single component. They however face problems when attempting to account for structure formation: in the linear regime, density fluctuations can…

Cosmology and Nongalactic Astrophysics · Physics 2015-09-16 Amr El-Zant

The abundance and distribution of collapsed objects such as galaxy clusters will become an important tool to investigate the nature of dark energy and dark matter. Number counts of very massive objects are sensitive not only to the equation…

Astrophysics · Physics 2010-05-12 L. R. Abramo , R. C. Batista , L. Liberato , R. Rosenfeld

Dark matter (DM) as a pressureless perfect fluid provides a good fit of the standard $\Lambda$CDM model to the astrophysical and cosmological data. In this paper, we investigate two extended properties of DM: a possible time dependence of…

Cosmology and Nongalactic Astrophysics · Physics 2019-10-31 Suresh Kumar , Rafael C. Nunes , Santosh Kumar Yadav

If a significant fraction of the dark matter in the Universe is made of an ultra-light scalar field, named fuzzy dark matter (FDM) with a mass $m_a$ of the order of $10^{-22}-10^{-21}$ eV, then its de Broglie wavelength is large enough to…

Cosmology and Nongalactic Astrophysics · Physics 2017-08-22 Eric Armengaud , Nathalie Palanque-Delabrouille , Christophe Yèche , David J. E. Marsh , Julien Baur

We study quantum corrections to the $\Lambda$CDM model model arising from a minimum measurable length in Heisenberg's uncertainty principle. We focus on a higher-order Generalized Uncertainty Principle, beyond the quadratic form. This…

General Relativity and Quantum Cosmology · Physics 2025-12-25 Andronikos Paliathanasis , Genly Leon , Yoelsy Leyva , Giuseppe Gaetano Luciano , Amare Abebe

The fuzzy dark matter (FDM) scenario has received increased attention in recent years due to the small-scale challenges of the vanilla Lambda cold dark matter ($\Lambda$CDM) cosmological model and the lack of any experimental evidence for…

Cosmology and Nongalactic Astrophysics · Physics 2023-01-20 Tibor Dome , Anastasia Fialkov , Philip Mocz , Björn Malte Schäfer , Michael Boylan-Kolchin , Mark Vogelsberger

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

We investigate the dynamics of the generalized $\Lambda$CDM model, which the $\Lambda$ term is running with the cosmological time. The $\Lambda(t)$ term emerges from the covariant theory of the scalar field $\phi$ with the self-interacting…

Cosmology and Nongalactic Astrophysics · Physics 2017-09-29 Marek Szydlowski , Aleksander Stachowski

We study the spherical collapse of an over-density of a barotropic fluid with linear equation of state in a cosmological background. Fully relativistic simulations are performed by using the Baumgarte-Shibata-Shapiro-Nakamura formalism…

General Relativity and Quantum Cosmology · Physics 2021-04-15 François Staelens , Jérémy Rekier , André Füzfa

Structure formation at small cosmological scales provides an important frontier for dark matter (DM) research. Scenarios with small DM particle masses, large momenta or hidden interactions tend to suppress the gravitational clustering at…

Cosmology and Nongalactic Astrophysics · Physics 2017-11-27 Riccardo Murgia , Alexander Merle , Matteo Viel , Maximilian Totzauer , Aurel Schneider

Observations have confirmed the accelerated expansion of the universe. The accelerated expansion can be modelled by invoking a cosmological constant or a dynamical model of dark energy. A key difference between these models is that the…

Cosmology and Nongalactic Astrophysics · Physics 2018-06-13 Manvendra Pratap Rajvanshi , Jasjeet Singh Bagla