Challenges for the kinetic unified dark matter model

Research output: Contribution to journalArticle

Abstract

Given that the dark matter and dark energy in the Universe affect cosmological observables only gravitationally, their phenomenology may be described by a single stress-energy tensor. True unification however requires a theory that reproduces the successful phenomenology of ΛCDM and that requirement places specific constraints on the stress structure of the matter. We show that a recently proposed unification through an offset quadratic kinetic term for a scalar field is exactly equivalent to a fluid with a closed-form barotropic equation of state plus cosmological constant. The finite pressure at high densities introduces a cutoff in the linear power spectrum, which may alleviate the dark matter substructure problem; we provide a convenient fitting function for such studies. Given that sufficient power must remain to reionize the Universe, the equation of state today is nonrelativistic with p ρ2 and a Jeans scale in the parsec regime for all relevant densities. Structure may then be evolved into the nonlinear regime with standard hydrodynamic techniques. In fact, the model is equivalent to the well-studied collisional dark matter with negligible mean free path. If recent observations of the triaxiality of dark matter halos and ram pressure stripping in galaxy clusters are confirmed, this model will be ruled out.

Original languageEnglish (US)
Article number063502
JournalPhysical Review D - Particles, Fields, Gravitation and Cosmology
Volume72
Issue number6
DOIs
StatePublished - Sep 15 2005

Fingerprint

Dark Matter
dark matter
Kinetics
Phenomenology
kinetics
Unification
phenomenology
Equation of State
equations of state
universe
triaxial stresses
ram
Dark Energy
Galaxies
Cosmological Constant
Substructure
stripping
substructures
dark energy
Power Spectrum

ASJC Scopus subject areas

  • Physics and Astronomy(all)
  • Nuclear and High Energy Physics
  • Mathematical Physics

Cite this

Challenges for the kinetic unified dark matter model. / Giannakis, Dimitrios; Hu, Wayne.

In: Physical Review D - Particles, Fields, Gravitation and Cosmology, Vol. 72, No. 6, 063502, 15.09.2005.

Research output: Contribution to journalArticle

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