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Related papers: Entropy Analysis of Dark Matter Halo Structures

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Considering Verlinde's entropic gravity proposal, we focus the effects of fermionic $q$ deformation on the Einstein's field equations and Friedmann equations. For this purpose, we represent the thermodynamical properties of the deformed…

General Relativity and Quantum Cosmology · Physics 2021-07-28 Mustafa Senay

We examine the coarse-grained phase-space density profiles of a set of recent, high-resolution simulations of galaxy-sized Cold Dark Matter (CDM) halos. Over two and a half decades in radius the phase-space density closely follows a…

Astrophysics · Physics 2009-11-06 James E. Taylor , Julio F. Navarro

Taking the flat rotation curve as input and treating the matter content in the galactic halo region as perfect fluid, we obtain space time metric at the galactic halo region in the framework of general relativity. We find that the resultant…

General Relativity and Quantum Cosmology · Physics 2010-11-26 F. Rahaman , K. K. Nandi , A. Bhadra , M. Kalam , K. Chakraborty

A longstanding puzzle of fundamental importance in modern cosmology has been the origin of the nearly universal density profiles of dark matter halos found in N-body simulations -- the so-called NFW profile. We show how this behavior may be…

Cosmology and Nongalactic Astrophysics · Physics 2010-10-25 Neal Dalal , Yoram Lithwick , Michael Kuhlen

We test with gravitational lensing data the dark matter (DM) halos embedding the luminous baryonic component of galaxy clusters; our benchmark is provided by their two-stage cosmogonical development that we compute with its variance, and by…

Cosmology and Nongalactic Astrophysics · Physics 2009-11-13 A. Lapi , A. Cavaliere

We describe a method for defining dynamical black hole entropy in gravitational effective field theories (EFTs). The entropy is constructed order by order in derivatives. For any fixed number of derivatives, the entropy satisfies a…

High Energy Physics - Theory · Physics 2024-04-16 Iain Davies , Harvey S. Reall

A brief overview of the discovery that macroscopic black holes are thermodynamical systems is presented. They satisfy the laws of thermodynamics and are associated with a temperature and an entropy equal to one quarter of their horizon area…

General Relativity and Quantum Cosmology · Physics 2023-10-31 Alejandro Perez

The initial radial density profiles of dark matter halos are laid down by gravitational collapse in hierarchical structure formation scenarios and are subject to further compression as baryons cool and settle to the halo centers. We here…

Astrophysics · Physics 2009-11-13 J. A. Sellwood , Stacy S. McGaugh

In this paper we calculate the density profiles of virialized halos both in the case of structure evolving hierarchically from a scale-free Gaussian delta-field having a power spectrum P(k)=A k^n in a Omega=1 Universe and in the case of the…

Astrophysics · Physics 2007-05-23 A. Del Popolo , M. Gambera , E. Recami , E. Spedicato

The Hamiltonian approach to black hole entropy, recently proposed in the framework of Poincar\'e gauge theory, is extended by including the scalar matter. The improved approach is used to analyse asymptotic charges and entropy of a typical…

General Relativity and Quantum Cosmology · Physics 2023-05-24 Milutin Blagojević , Branislav Cvetković

In this paper, we first obtain the energy density by the approach of the new agegraphic dark energy model, and then the $f(T,B)$ gravity model is studied as an alternative to the dark energy in a viscous fluid by flat-FRW background, in…

General Relativity and Quantum Cosmology · Physics 2020-06-17 A. Pourbagher , Alireza Amani

The structure of dark matter halos as predicted from cosmological models is discussed and compared with observed rotation curves of dark matter-dominated dwarf galaxies. The theoretical models predict that dark matter halos represent a…

Astrophysics · Physics 2007-05-23 Andreas Burkert , Joseph Silk

I apply the modified spherical infall model to test the dependence of the shape of density profiles of dark matter halos on redshift. The model predicts that the density profile of a halo of a given mass steepens with time and its…

Astrophysics · Physics 2007-05-23 Ewa L. Lokas

We construct a proof of the second law of thermodynamics in an arbitrary diffeomorphism invariant theory of gravity working within the approximation of linearized dynamical fluctuations around stationary black holes. We achieve this by…

High Energy Physics - Theory · Physics 2021-10-05 Sayantani Bhattacharyya , Prateksh Dhivakar , Anirban Dinda , Nilay Kundu , Milan Patra , Shuvayu Roy

We investigate the structure of cold dark matter halos using advanced models of spherical collapse and accretion in an expanding Universe. These base on solving time-dependent equations for the moments of the phase-space distribution…

Cosmology and Nongalactic Astrophysics · Physics 2015-05-30 A. Lapi , A. Cavaliere

We have recently shown that both the Prugniel-Simien model and Sersic's function (hereafter referred to as the Einasto model when applied to internal density profiles) describe simulated dark matter halos better than an NFW-like model with…

Astrophysics · Physics 2012-04-26 Alister W. Graham , David Merritt , Ben Moore , Juerg Diemand , Balsa Terzic

We take the view that the standard von Neumann definition, in which the entropy $S^{vN}$ of a pure state is zero, is in evident conflict with the statement of the second law that the entropy of the universe $S_{univ}$ increases in…

Quantum Physics · Physics 2018-10-25 George L. Barnes , Phillip C. Lotshaw , Michael E. Kellman

The first and second laws of black hole thermodynamics are verified to emerge from a generic semiclassical theory of gravity for which a Hamiltonian can be defined. The first law is established for stationary spacetimes, and the second law…

General Relativity and Quantum Cosmology · Physics 2021-09-07 Bruno Arderucio-Costa

Black hole thermodynamics is the area of study that seeks to reconcile the laws of thermodynamics with the existence of black hole event horizons. Here we calculate the entropy corresponding to the interior of a Schwarzschild black hole for…

General Physics · Physics 2019-02-28 Sandip Dutta , Ritabrata Biswas