scholarly journals Derivation of the core mass-halo mass relation of fermionic and bosonic dark matter halos from an effective thermodynamical model

2019 ◽  
Vol 100 (12) ◽  
Author(s):  
Pierre-Henri Chavanis
Keyword(s):  
Dark Matter ◽  
Mass Relation ◽  
Dark Matter Halos ◽  
Core Mass ◽  
The Core ◽  
Thermodynamical Model

scholarly journals On the formation and stability of fermionic dark matter halos in a cosmological framework

2020 ◽  
Author(s):  
Carlos R Argüelles ◽  
Manuel I Díaz ◽  
Andreas Krut ◽  
Rafael Yunis
Keyword(s):  
Black Hole ◽  
Dark Matter ◽  
Space Distribution ◽  
Coarse Grained ◽  
Dark Matter Halos ◽  
The Core ◽  
The Galaxy ◽  
Gravitating Systems ◽  
The Given ◽  
First Time

Abstract The formation and stability of collisionless self-gravitating systems is a long standing problem, which dates back to the work of D. Lynden-Bell on violent relaxation, and extends to the issue of virialization of dark matter (DM) halos. An important prediction of such a relaxation process is that spherical equilibrium states can be described by a Fermi-Dirac phase-space distribution, when the extremization of a coarse-grained entropy is reached. In the case of DM fermions, the most general solution develops a degenerate compact core surrounded by a diluted halo. As shown recently, the latter is able to explain the galaxy rotation curves while the DM core can mimic the central black hole. A yet open problem is whether this kind of astrophysical core-halo configurations can form at all, and if they remain stable within cosmological timescales. We assess these issues by performing a thermodynamic stability analysis in the microcanonical ensemble for solutions with given particle number at halo virialization in a cosmological framework. For the first time we demonstrate that the above core-halo DM profiles are stable (i.e. maxima of entropy) and extremely long lived. We find the existence of a critical point at the onset of instability of the core-halo solutions, where the fermion-core collapses towards a supermassive black hole. For particle masses in the keV range, the core-collapse can only occur for Mvir ≳ E9M⊙ starting at zvir ≈ 10 in the given cosmological framework. Our results prove that DM halos with a core-halo morphology are a very plausible outcome within nonlinear stages of structure formation.

Clustering dependence of Chandra COSMOS Legacy AGN on host galaxy properties

2019 ◽  
Vol 15 (S356) ◽  
pp. 226-226
Author(s):  
Viola Allevato
Keyword(s):  
Dark Matter ◽  
Formation Rate ◽  
Stellar Mass ◽  
Active Galaxies ◽  
Host Galaxy ◽  
Mass Star ◽  
Mass Relation ◽  
Dark Matter Halos ◽  
X Ray

AbstractThe presence of a super massive BH in almost all galaxies in the Universe is an accepted paradigm in astronomy. How these BHs form and how they co-evolve with the host galaxy is one of the most intriguing unanswered problems in modern Cosmology and of extreme relevance to understand the issue of galaxy formation. Clustering measurements can powerfully test theoretical model predictions of BH triggering scenarios and put constraints on the typical environment where AGN live in, through the connection with their host dark matter halos. In this talk, I will present some recent results on the AGN clustering dependence on host galaxy properties, such as galaxy stellar mass, star formation rate and specific BH accretion rate, based on X-ray selected Chandra COSMOS Legacy Type 2 AGN. We found no significant AGN clustering dependence on galaxy stellar mass and specif BHAR for Type 2 COSMOS AGN at mean z ∼ 1.1, with a stellar - halo mass relation flatter than predicted for non active galaxies in the Mstar range probed by our sample. We also observed a negative clustering dependence on SFR, with AGN hosting halo mass increasing with decreasing SFR. Mock catalogs of active galaxies in hosting dark matter halos with logMh[Msun] > 12.5, matched to have the same X-ray luminosity, stellar mass and BHAR of COSMOS AGN predict the observed Mstar - Mh, BHAR - Mh and SFR-Mh relations, at z ∼ 1.

scholarly journals Studying the core-cusp problem in cold dark matter halos usingN-body simulations on GPU clusters

2013 ◽  
Vol 454 ◽  
pp. 012014 ◽  
Author(s):  
Go Ogiya ◽  
Masao Mori ◽  
Yohei Miki ◽  
Taisuke Boku ◽  
Naohito Nakasato
Keyword(s):  
Dark Matter ◽  
Cold Dark Matter ◽  
Dark Matter Halos ◽  
The Core ◽  
Gpu Clusters

scholarly journals Are the most super-massive dark compact objects harbored at the center of dark matter halos?

2014 ◽  
Vol 23 (12) ◽  
pp. 1442020 ◽  
Author(s):  
C. R. Argüelles ◽  
R. Ruffini
Keyword(s):  
Dark Matter ◽  
Mass Density ◽  
Compact Objects ◽  
Fermion Mass ◽  
Dark Matter Halos ◽  
Core Mass ◽  
Density Profiles ◽  
Equilibrium Configurations ◽  
Isothermal System ◽  
The One

We study an isothermal system of semi-degenerate self-gravitating fermions in general relativity (GR). The most general solutions present is mass density profiles with a central degenerate compact core governed by quantum statistics followed by an extended plateau, and ending in a power law behavior r-2. By fixing the fermion mass m in the keV regime, the different solutions depending on the free parameters of the model: the degeneracy and temperature parameters at the center, are systematically constructed along the one-parameter sequences of equilibrium configurations up to the critical point, which is represented by the maximum in a central density (ρ0) versus core mass (Mc) diagram. We show that for fully degenerate cores, the Oppenheimer–Volkoff (OV) mass limit [Formula: see text] is obtained, while instead for low degenerate cores, the critical core mass increases showing the temperature effects in a nonlinear way. The main result of this work is that when applying this theory to model the distribution of dark matter (DM) in big elliptical galaxies from miliparsec distance-scales up to 102Kpc, we do not find any critical core-halo configuration of self-gravitating fermions, able to explain both the most super-massive dark object at their center together with the DM halo simultaneously.

scholarly journals New Model of Density Distribution for Fermionic Dark Matter Halos

2018 ◽  
Vol 63 (9) ◽  
pp. 769 ◽  
Author(s):  
A. V. Rudakovskyi ◽  
D. O. Savchenko
Keyword(s):  
Dark Matter ◽  
Density Distribution ◽  
Density Profile ◽  
Initial Phase ◽  
Matter Density ◽  
Dark Matter Halos ◽  
New Model ◽  
Dwarf Spheroidal Galaxies ◽  
The Core ◽  
Dirac Distribution

We formulate a new model of density distribution for halos made of warm dark matter (WDM) particles. The model is described by a single microphysical parameter – the mass (or, equivalently, the maximal value of the initial phase-space density distribution) of dark matter particles. Given the WDM particle mass and the parameters of a dark matter density profile at the halo periphery, this model predicts the inner density profile. In the case of initial Fermi–Dirac distribution, we successfully reproduce cored dark matter profiles from N-body simulations. We calculate also the core radii of warm dark matter halos of dwarf spheroidal galaxies for particle masses mFD = 100, 200, 300, and 400 eV.

The core-cusp problem in Cold Dark Matter halos and supernova feedback

2010 ◽  
Author(s):  
Go Ogiya ◽  
Masao Mori ◽  
Nobuyuki Kawai ◽  
Shigehiro Nagataki
Keyword(s):  
Dark Matter ◽  
Cold Dark Matter ◽  
Dark Matter Halos ◽  
The Core ◽  
Supernova Feedback

The Core Density of Dark Matter Halos: A Critical Challenge to the ΛCDM Paradigm?

2000 ◽  
Vol 528 (2) ◽  
pp. 607-611 ◽  
Author(s):  
Julio F. Navarro ◽  
Matthias Steinmetz
Keyword(s):  
Dark Matter ◽  
Dark Matter Halos ◽  
Core Density ◽  
The Core ◽  
Critical Challenge
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