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Related papers: Spherical Collapse Models with Clustered Dark Ener…

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We derive, using the spherical collapse model, a generalized Layzer-Irvine equation which can be used to describe the gravitational collapse of cold dark matter in a dark energy background. We show that the usual Layzer-Irvine equation is…

Cosmology and Nongalactic Astrophysics · Physics 2015-06-16 P. P. Avelino , C. F. V. Gomes

Dark energy(DE) remains one of the most important subjects in modern cosmology, and its physical origin is still under intensive discussion. While an astrophysical origin of DE is a highly challenging scenario, black holes stand out the…

Cosmology and Nongalactic Astrophysics · Physics 2025-11-18 Shintaro K. Hayashi

We present forecasts on the capability of future wide-area high-sensitivity X-ray surveys of galaxy clusters to yield constraints on the parameters defining the Dark Energy (DE) equation of state (EoS). Our analysis is carried out for…

Cosmology and Nongalactic Astrophysics · Physics 2012-07-10 B. Sartoris , S. Borgani , P. Rosati , J. Weller

Cosmological background observations cannot fix the dark energy equation of state, which is related to a degeneracy in the definition of the dark sector components. Here we show that this degeneracy can be broken at perturbation level by…

Cosmology and Nongalactic Astrophysics · Physics 2014-06-10 S. Carneiro , H. A. Borges

We describe the Dark Energy Survey (DES), a proposed optical-near infrared survey of 5000 sq. deg of the South Galactic Cap to ~24th magnitude in SDSS griz, that would use a new 3 sq. deg CCD camera to be mounted on the Blanco 4-m telescope…

Astrophysics · Physics 2012-08-27 The Dark Energy Survey Collaboration

Using the nonextensive Tsallis entropy and the holographic hypothesis, we propose a new dark energy (DE) model with time scale as infrared (IR) cutoff. Considering the age of the Universe as well as the conformal time as IR cutoffs, we…

General Physics · Physics 2019-04-01 M. Abdollahi Zadeh , A. Sheykhi , H. Moradpour

We review the paradigm of holographic dark energy (HDE), which arises from a theoretical attempt of applying the holographic principle (HP) to the dark energy (DE) problem. Making use of the HP and the dimensional analysis, we derive the…

Cosmology and Nongalactic Astrophysics · Physics 2017-08-24 Shuang Wang , Yi Wang , Miao Li

The cooling envelope model for tidal disruption events (TDE) postulates that while the stellar debris streams rapidly dissipate their bulk kinetic energy (``circularize"), this does not necessarily imply rapid feeding of the supermassive…

High Energy Astrophysical Phenomena · Physics 2024-01-22 Nikhil Sarin , Brian D. Metzger

The problem of dark energy can be roughly stated as the proposition and validation of a cosmological model that can explain the phenomenon of the accelerated expansion of the Universe. This problem is an open discussion topic in modern…

General Relativity and Quantum Cosmology · Physics 2014-12-19 Genly Leon

Cosmological information is encoded in the structure of galaxy clusters. In Universes with less matter and larger initial density perturbations, clusters form earlier and have more time to accrete material, leading to a more extended infall…

We investigate the properties of massive, dense clouds formed in a barred galaxy and their possible relation to star formation, performing a two-dimensional hydrodynamical simulation with the gravitational potential obtained from the 2Mass…

Astrophysics of Galaxies · Physics 2015-06-05 M. Nimori , A. Habe , K. Sorai , Y. Watanabe , A. Hirota , D. Namekata

The state of the hot gas in clusters of galaxies is investigated with a set of model clusters, created by assuming a polytropic equation of state (Gamma=1.2) and hydrostatic equilibrium inside gravitational potential wells drawn from a dark…

Cosmology and Nongalactic Astrophysics · Physics 2009-07-22 Paul Bode , Jeremiah P. Ostriker , Alexey Vikhlinin

We investigate galaxy clustering and galaxy-mass correlations in the LCDM cosmological model using a large volume SPH simulation. For the most part, the predicted biases between galaxies and dark matter lead to good agreement with current…

Astrophysics · Physics 2009-11-07 David H. Weinberg , Romeel Dav'e , Neal Katz , Lars Hernquist

This paper considers the spherically symmetric gravitational collapse in the background of Chaplygin gas as dark energy component. The dark energy is assumed to be generalized and modified Chaplygin gas. The exterior of the star is…

General Relativity and Quantum Cosmology · Physics 2023-03-14 Anjali Pandey , Rajesh Kumar , Sudhir Kumar Srivastava

We provide a generic but physically clear discussion of the clustering properties of dark energy models. We explicitly show that in quintessence-type models the dark energy fluctuations, on scales smaller than the Hubble radius, are of the…

Astrophysics · Physics 2008-11-26 P. P. Avelino , L. M. G. Beca , C. J. A. P. Martins

Splashback refers to the process of matter that is accreting onto a dark matter halo reaching its first orbital apocenter and turning around in its orbit. The cluster-centric radius at which this process occurs, r_sp, defines a halo…

This conference proceedings paper provides a short summary of the constraints presented by Menci et al. (2020) and Menci et al. (2022) to dynamical dark energy models. Dynamical dark energy (DDE) models have been proposed to address several…

Cosmology and Nongalactic Astrophysics · Physics 2023-01-11 Paola Santini , Nicola Menci , Marco Castellano

We propose a new class of metastable dark energy (DE) phenomenological models in which the DE decay rate does not depend on external parameters such as the scale factor or the curvature of the Universe. Instead, the DE decay rate is assumed…

Cosmology and Nongalactic Astrophysics · Physics 2018-01-23 Arman Shafieloo , Dhiraj Kumar Hazra , Varun Sahni , Alexei A. Starobinsky

Theoretically, stars have been formed from the collapse of cores in the molecular clouds. Historically, the core had been assumed as an singular isothermal sphere (SIS), and the collapse had been investigated by a self-similar manner. This…

Astrophysics of Galaxies · Physics 2015-05-19 Mohsen Nejad-Asghar

We present the Dark MaGICC project, which aims to investigate the effect of Dark Energy (DE) modeling on galaxy formation via hydrodynamical cosmological simulations. Dark MaGICC includes four dynamical Dark Energy scenarios with time…

Cosmology and Nongalactic Astrophysics · Physics 2015-06-18 Camilla Penzo , Andrea V. Macciò , Luciano Casarini , Greg S. Stinson , James Wadsley
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