Dwarf spheroidal galaxies as degenerate gas of free fermions

Abstract

In this paper we analyze a simple scenario in which Dark Matter (DM) consists of free fermions with mass $m_f$. We assume that on galactic scales these fermions are capable of forming a degenerate Fermi gas, in which stability against gravitational collapse is ensured by the Pauli exclusion principle. The mass density of the resulting configuration is governed by a non-relativistic Lane-Emden equation, thus leading to a universal cored profile that depends only on one free parameter in addition to $m_f$. After reviewing the basic formalism, we test this scenario against experimental data describing the velocity dispersion of the eight classical dwarf spheroidal galaxies of the Milky Way. We find that, despite its extreme simplicity, the model exhibits a good fit to the data and realistic predictions for the size of DM halos providing that $m_f\simeq 200$ eV. Furthermore, we show that in this setup larger galaxies correspond to the non-degenerate limit of the gas. We propose a concrete realization of this model in which DM is produced non-thermally via inflaton decay. We show that imposing the correct relic abundance and the bound on the free-streaming length constrains the inflation model in terms of inflaton mass, its branching ratio into DM and the reheating temperature.

arXiv comment17 pages, 7 figures. v3: Comparison with numerical data on mean densities added (Fig. 7). Version to be published in JCAP

References in corpus (43)

• Planck 2013 results. XVI. Cosmological parameters
• Dwarf Galaxies of the Local Group
• Observational evidence for self-interacting cold dark matter
• Cold and Fuzzy Dark Matter
• The Structure of Dark Matter Haloes in Dwarf Galaxies
• Cold collapse and the core catastrophe
• Halo Formation in Warm Dark Matter Models
• The Milky Way's bright satellites as an apparent failure of LCDM
• A Universal Mass Profile for Dwarf Spheroidal Galaxies?
• Can dark matter be a Bose-Einstein condensate?
• The dependence of dark matter profiles on the stellar to halo mass ratio: a prediction for cusps vs cores
• Bose-Einstein Condensation of Dark Matter Axions
• Late time Cosmological Phase Transition and Galactic Halo as Bose-liquid
• Substructure and halo density profiles in a Warm Dark Matter Cosmology
• A constant dark matter halo surface density in galaxies
• A lower bound on the mass of Dark Matter particles
• Formation and structure of halos in a warm dark matter cosmology
• Cosmological Constraints on Bose-Einstein-Condensed Scalar Field Dark Matter
• Erasing Dark Matter Cusps in Cosmological Galactic Halos with Baryons
• Angular Momentum and Vortex Formation in Bose-Einstein-Condensed Cold Dark Matter Haloes
• Evolution of cosmological perturbations in Bose-Einstein condensate dark matter
• Late-time Phase transition and the Galactic halo as a Bose Liquid: (II) the Effect of Visible Matter
• Bose-Einstein condensation of dark matter solves the core/cusp problem
• On the Theory of Fermionic Preheating
• Growth of perturbations in an expanding universe with Bose-Einstein condensate dark matter
• Phase transitions in self-gravitating systems. Self-gravitating fermions and hard spheres models
• Radial distribution and strong lensing statistics of satellite galaxies and substructure using high resolution LCDM hydrodynamical simulations
• Dissecting Galaxy Formation: I. Comparison Between Pure Dark Matter and Baryonic Models
• Self-gravity as an explanation of the fractal structure of the interstellar medium
• Fermionic warm dark matter produces galaxy cores in the observed scales because of quantum mechanics
• Observational rotation curves and density profiles vs. the Thomas-Fermi galaxy structure theory
• Cosmological dynamics of dark matter Bose-Einstein Condensation
• Axions: Bose Einstein Condensate or Classical Field?
• Early galaxy formation in warm dark matter cosmologies
• Dark matter as a Bose--Einstein Condensate: the relativistic non-minimally coupled case
• Statistical mechanics and thermodynamic limit of self-gravitating fermions in D dimensions
• Quantum WDM fermions and gravitation determine the observed galaxy structures
• Dark matter from late decays and the small-scale structure problems
• Bose Einstein condensation of the classical axion field in cosmology?
• Galactic cold dark matter as a Bose-Einstein condensate of WISPs
• Evolution and thermalization of dark matter axions in the condensed regime
• Dwarf spheroidal galaxies and Bose-Einstein condensate dark matter
• Equation of state, universal profiles, scaling and macroscopic quantum effects in Warm Dark Matter galaxies

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• Galaxy rotation curves and universal scaling relations: comparison between phenomenological and fermionic dark matter profiles
• Experimental targets for dark photon dark matter
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• Estimation of the Mass of Dark Matter Using the Observed Mass Profiles of Late-Type Galaxies
• Constraining ultra light fermionic dark matter with Milky-Way observations
• Triggering Electron Capture Supernovae: Dark Matter Effects in Degenerate White-Dwarf-like Cores of Super-Asymptotic Giant Branch Stars
• Constraining light fermionic dark matter with binary pulsars
• Hunt for dark subhalos in the galactic stellar field using computer vision
• Detecting meV-Scale Dark Matter via Coherent Scattering with an Asymmetric Torsion Balance
• Assessment of Dark Matter Models Using Dark Matter Correlations across Dwarf Spheroidal Galaxies
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