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The evolution of the virial overdensity $\Delta_{\rm vir}$ for $\Lambda$CDM and seven dynamical dark-energy models is investigated in the extended spherical collapse model (SCM). Here the virialization process is naturally achieved by…

Cosmology and Nongalactic Astrophysics · Physics 2019-10-10 Francesco Pace , Carlo Schimd , David F. Mota , Antonino Del Popolo

In this work we review the theory of the spherical collapse model and critically analyse the aspects of the numerical implementation of its fundamental equations. By extending a recent work by Herrera et al. 2017, we show how different…

Cosmology and Nongalactic Astrophysics · Physics 2017-12-21 Francesco Pace , Sven Meyer , Matthias Bartelmann

We compute the one-point PDF of an initially Gaussian dark matter density field using spherical collapse (SC). We compare the results to other forms available in the literature and also compare the PDFs in the $\Lambda$CDM model with an…

Cosmology and Nongalactic Astrophysics · Physics 2020-09-08 Ankush Mandal , Sharvari Nadkarni-Ghosh

In the present work, gravitational collapse of an inhomogeneous spherical star model, consisting of inhomogeneous dust fluid (dark matter) in the background of dark energy is considered. The collapsing process is examined first separately…

General Relativity and Quantum Cosmology · Physics 2007-05-23 Tanwi Bandyopadhyay , Subenoy Chakraborty

In this work we consider the impact of spatially-uniform but time-varying dark energy (or `dynamical dark energy', DDE) on large-scale structure in a spatially flat universe, using large cosmological hydrodynamical simulations that form…

Cosmology and Nongalactic Astrophysics · Physics 2020-08-12 Simon Pfeifer , Ian G. McCarthy , Sam G. Stafford , Shaun T. Brown , Andreea S. Font , Juliana Kwan , Jaime Salcido , Joop Schaye

We study, for the first time, how shear and angular momentum modify typical parameters of the spherical collapse model, in dark energy dominated universes. In particular, we study the linear density threshold for collapse…

Cosmology and Nongalactic Astrophysics · Physics 2014-02-04 A. Del Popolo , F. Pace , J. A. S. Lima

We consider the holographic dark energy (HDE) model in the framework of DGP braneworld with Granda-Oliveros infrared (IR) cutoff, $L=(\alpha \dot{H}+\beta H^2)^{-1/2}$. With this choice for IR cutoff, we are able to derive evolution of the…

General Relativity and Quantum Cosmology · Physics 2015-06-05 S. Ghaffari , M. H. Dehghani , A. Sheykhi

In this paper we consider quintessence reconstruction of interacting holographic dark energy in a non-flat background. As system's IR cutoff we choose the radius of the event horizon measured on the sphere of the horizon, defined as…

Cosmology and Nongalactic Astrophysics · Physics 2015-06-18 Ahmad Sheykhi , Hamzeh Alavirad , Ali Bagheri , Esmaeil Ebrahimi

In this paper, we study an interacting holographic dark energy model in the framework of fractal cosmology. The features of fractal cosmology could pass ultraviolet divergencies and also make a better understanding of the universe in…

General Relativity and Quantum Cosmology · Physics 2018-10-16 Ehsan Sadri , Martiros Khurshudyan , Surajit Chattopadhyay

We compute the number density of massive Black Holes (BHs) at the centre of galaxies at z=6 in different Dynamical Dark Energy (DDE) cosmologies, and compare it with existing observational lower limits, to derive constraints on the…

Cosmology and Nongalactic Astrophysics · Physics 2015-06-03 Alessandra Lamastra , Nicola Menci , Fabrizio Fiore , Cinzia Di Porto , Luca Amendola

We use the spherical collapse method to investigate the non-linear density perturbations of pressureless matter in the cosmological models with the extended quintessence as dark energy in the metric and Palatini formalisms. We find that for…

General Relativity and Quantum Cosmology · Physics 2015-11-09 Yize Fan , Puxun Wu , Hongwei Yu

The anti-de Sitter (AdS) black hole plays an important role in the holographic principle. In this study, the upper bound in energy corresponding to the mass of the Schwarzschild black hole is modified to be that of the AdS black hole. Via…

General Relativity and Quantum Cosmology · Physics 2022-11-18 Ratchaphat Nakarachinda , Chakrit Pongkitivanichkul , Daris Samart , Lunchakorn Tannukij , Pitayuth Wongjun

In this paper, we study the effects which are produced by the interaction between a brane Universe and the bulk in which the Universe is embedded. Taking into account the effects produced by the interaction between a brane Universe and the…

General Relativity and Quantum Cosmology · Physics 2015-11-03 Antonio Pasqua , Surajit Chattopadhyay , Ratbay Myrzakulov

We investigate Dark Energy by associating it with vacuum energy or Cosmological constant ${\Lambda}$ which is taken to be dynamic in nature. Our approach is phenomenological and falls within the domain of variable-$\Lambda$ Cosmology.…

Cosmology and Nongalactic Astrophysics · Physics 2022-02-08 Arkajit Aich

The consideration of the holographic dark energy approach and matter creation effects in a single cosmological model is carried out in this work accordingly, we discuss some cases of interest. We test this cosmological proposal against…

General Relativity and Quantum Cosmology · Physics 2022-10-19 V. H. Cárdenas , Miguel Cruz , Samuel Lepe

We investigate the effects of dynamical dark energy (DDE) on the growth of cosmic structure using a two-fluid model. This framework allows the dark energy equation of state to smoothly cross the phantom divide, in agreement with recent DESI…

Cosmology and Nongalactic Astrophysics · Physics 2026-03-06 Frans van Die , Vincent Desjacques

The paper investigates the Tsallis holographic dark energy (THDE) model in accordance with the apparent horizon as an infrared cut-off, in a non-flat universe. The cosmological evolution of the deceleration parameter and equation of state…

General Physics · Physics 2020-01-16 Vipin Chandra Dubey , Umesh Kumar Sharma , A. Beesham

Understanding the accelerating expansion of the universe remains one of the foremost challenges in modern cosmology. This study investigates Barrow Holographic Dark Energy (BHDE), a model inspired by quantum gravitational corrections,…

General Relativity and Quantum Cosmology · Physics 2024-12-02 N. Myrzakulov , S. H. Shekh , Anirudh Pradhan

Within the framework of FRW cosmology, we study the QCD modified ghost scalar field models of dark energy in the presence of both interaction and viscosity. For a spatially non-flat FRW universe containing modified ghost dark energy (MGDE)…

General Physics · Physics 2013-04-30 K. Karami , S. Asadzadeh , M. Mousivand , Z. Safari

Dark energy has a dramatic effect on the dynamics of the universe, causing the recently discovered acceleration of the expansion. The dynamics are also central to the behavior of the growth of large scale structure, offering the possibility…

Astrophysics · Physics 2009-11-07 Eric V. Linder , Adrian Jenkins
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