Cores in Dwarf Galaxies from Fermi Repulsion

Abstract

We show that Fermi repulsion can lead to cored density profiles in dwarf galaxies for sub-keV fermionic dark matter. We treat the dark matter as a quasi-degenerate self-gravitating Fermi gas and calculate its density profile assuming hydrostatic equilibrium. We find that suitable dwarf galaxy cores of larger than 130 pc can be achieved for fermion dark matter with mass in the range 70 eV - 400 eV. While in conventional dark matter scenarios, such sub-keV thermal dark matter would be excluded by free streaming bounds, the constraints are ameliorated in models with dark matter at lower temperature than conventional thermal scenarios, such as the Flooded Dark Matter model that we have previously considered. Modifying the arguments of Tremaine and Gunn we derive a conservative lower bound on the mass of fermionic dark matter of 70 eV and a stronger lower bound from Lyman-$\alpha$ clouds of about 470 eV, leading to slightly smaller cores than have been observed. We comment on this result and how the tension is relaxed in dark matter scenarios with non-thermal momentum distributions.

12 pages, 7 figures

References in corpus (29)

• The Cosmic Linear Anisotropy Solving System (CLASS) II: Approximation schemes
• Observational evidence for self-interacting cold dark matter
• Towards the Theory of Reheating After Inflation
• Cold and Fuzzy Dark Matter
• Electroweak baryogenesis
• Warm Dark Matter as a solution to the small scale crisis: new constraints from high redshift Lyman-alpha forest data
• A New Dark Matter Candidate: Non-thermal Sterile Neutrinos
• A Universal Mass Profile for Dwarf Spheroidal Galaxies?
• Cosmological Simulations with Self-Interacting Dark Matter II: Halo Shapes vs. Observations
• Cold dark matter: controversies on small scales
• Fluid Dark Matter
• Stellar Feedback in Dwarf Galaxy Formation
• The formation of disc galaxies in high resolution moving-mesh cosmological simulations
• Asymmetric Inflationary Reheating and the Nature of Mirror Universe
• The coupling between the core/cusp and missing satellite problems
• Lyman-alpha Forests cool Warm Dark Matter
• The Lyman-alpha forest opacity and the metagalactic hydrogen ionization rate at z~2-4
• The Star Formation & Chemical Evolution History of the Fornax Dwarf Spheroidal Galaxy
• Late-time Phase transition and the Galactic halo as a Bose Liquid: (II) the Effect of Visible Matter
• Flavored Dark Matter, and Its Implications for Direct Detection and Colliders
• Dark Matter from Minimal Flavor Violation
• The core size of the Fornax dwarf Spheroidal
• Early flattening of dark matter cusps in dwarf spheroidal galaxies
• Cores and Cusps in the Dwarf Spheroidals
• Fermionic warm dark matter produces galaxy cores in the observed scales because of quantum mechanics
• Models of dark matter halos based on statistical mechanics: II. The fermionic King model
• Models of dark matter halos based on statistical mechanics: I. The classical King model
• Dwarf spheroidal galaxies as degenerate gas of free fermions
• Gravitationally bound BCS state as dark matter

Cited by in corpus (32)

• Constraining a Thin Dark Matter Disk with Gaia
• Can Light Dark Matter Solve the Core-Cusp Problem?
• A predictive model of BEC dark matter halos with a solitonic core and an isothermal atmosphere
• Phase space mass bound for fermionic dark matter from dwarf spheroidal galaxies
• Neutrino masses, leptogenesis and dark matter from small lepton number violation?
• An Ultralight Axion in Supersymmetry and Strings and Cosmology at Small Scales
• XENON1T Anomaly and its Implication for Decaying Warm Dark Matter
• Mass dimension one fermions: Constructing darkness
• Ultralight Fermionic Dark Matter
• On the formation and stability of fermionic dark matter halos in a cosmological framework
• New mass bound on fermionic dark matter from a combined analysis of classical dSphs
• Jeans mass-radius relation of self-gravitating Bose-Einstein condensates and typical parameters of the dark matter particle
• Statistical mechanics of self-gravitating systems in general relativity: I. The quantum Fermi gas
• Assessing the Fornax globular cluster timing problem in different models of dark matter
• Exploring the ultra-light to sub-MeV dark matter window with atomic clocks and co-magnetometers
• Fermionic Dark Matter: Physics, Astrophysics, and Cosmology
• Strongly-Interacting Ultralight Millicharged Particles
• Degenerate Sub-keV Fermion Dark Matter from a Solution to the Hubble Tension
• Condensed dark matter with a Yukawa interaction
• Predictive model of fermionic dark matter halos with a quantum core and an isothermal atmosphere
• Experimental targets for dark photon dark matter
• Degenerate Fermion Dark Matter from a Broken $U(1{)}_{\mathrm{B}-\mathrm{L}}$ Gauge Symmetry
• Degeneracy pressure of mass dimension one fermionic fields and the dark matter halo of galaxies
• Ultra light Thomas-Fermi Dark Matter
• Profile of a Galactic Spherical Cloud of Self-Gravitating Fermions
• Constraining ultra light fermionic dark matter with Milky-Way observations
• On the Tremaine-Gunn Limit with Mass-Varying Particles
• Hunt for dark subhalos in the galactic stellar field using computer vision
• On the Stability of Fermionic Non-Isothermal Dark Matter Halos
• New model of density distribution for fermionic dark matter halos
• Confusing dark matter particle properties with modifications to General Relativity
• Structure-wide dark matter density depletion induced by local degeneracies