Polytropic dark matter flows illuminate dark energy and accelerated expansion
arXiv:1411.6789 · doi:10.1051/0004-6361/201424402
Abstract
Currently, a large amount of data implies that the matter constituents of the cosmological dark sector might be collisional. An attractive feature of such a possibility is that, it can reconcile dark matter (DM) and dark energy (DE) in terms of a single component, accommodated in the context of a polytropic-DM fluid. Accordingly, we explore the time evolution and the dynamical characteristics of a spatially-flat cosmological model, in which, in principle, there is no DE at all. Instead, in this model, the DM itself possesses some sort of fluid-like properties, i.e., the fundamental units of the Universe matter-energy content are the volume elements of a DM fluid, performing polytropic flows. In this case, the energy of this fluid's internal motions is also taken into account as a source of the universal gravitational field. This form of energy can compensate for the extra energy needed to compromise spatial flatness, namely, to justify that, today, the total-energy density parameter is exactly unity. The polytropic cosmological model, depends on only one free parameter, the corresponding exponent, Γ. What makes this model particularly interesting, is that, for Γ< 0.541, the (conventional) pressure becomes negative enough, so that the Universe accelerates its expansion at cosmological redshifts below a transition value. Several physical reasons impose further constraints on the value of Γ, which, eventually, is settled down to the range -0.089 < Γ< 0. Such a cosmological model does not suffer either from the age problem or from the coincidence problem. At the same time, this model reproduces to high accuracy the distance measurements performed with the aid of the supernovae Type Ia standard candles, and most naturally interprets, not only when, but also, why the Universe transits from deceleration to acceleration, thus arising as a mighty contestant for a DE model.
17 pages, 8 figures; accepted in Astronomy & Astrophysics
References in corpus (34)
- Wilkinson Microwave Anisotropy Probe (WMAP) Three Year Results: Implications for Cosmology
- Dynamics of dark energy
- Five-Year Wilkinson Microwave Anisotropy Probe (WMAP) Observations: Cosmological Interpretation
- Observation of an anomalous positron abundance in the cosmic radiation
- Dark Energy and the Accelerating Universe
- New Hubble Space Telescope Discoveries of Type Ia Supernovae at z > 1: Narrowing Constraints on the Early Behavior of Dark Energy
- Five-Year Wilkinson Microwave Anisotropy Probe (WMAP) Observations: Likelihoods and Parameters from the WMAP data
- A Theory of Dark Matter
- Improved Cosmological Constraints from New, Old and Combined Supernova Datasets
- Cosmological Constraints from the SDSS Luminous Red Galaxies
- Spectra and Light Curves of Six Type Ia Supernovae at 0.511 < z < 1.12 and the Union2 Compilation
- Observational Constraints on the Nature of the Dark Energy: First Cosmological Results from the ESSENCE Supernova Survey
- Improved Dark Energy Constraints from ~100 New CfA Supernova Type Ia Light Curves
- Cosmological parameters from combining the Lyman-alpha forest with CMB, galaxy clustering and SN constraints
- CfA3: 185 Type Ia Supernova Light Curves from the CfA
- Is dark matter with long-range interactions a solution to all small-scale problems of ΛCDM cosmology?
- Multi-Component Dark Matter
- Kinematic Constraints to the Transition Redshift from SNe Ia Union Data
- Evidence Of Dark Matter Annihilations In The WMAP Haze
- Mapping the Cosmological Expansion
- Multi-wavelength signals of dark matter annihilations at the Galactic center
- PAMELA Satellite Data as a Signal of Non-Thermal Wino LSP Dark Matter
- On using the CMB shift parameter in tests of models of dark energy
- Anisotropy probe of galactic and extra-galactic Dark Matter annihilations
- TASI 2008 Lectures on Dark Matter
- Reconstructing interacting new agegraphic polytropic gas model in non-flat FRW universe
- Light curves of five type Ia supernovae at intermediate redshift
- Stellar polytropes and Navarro-Frenk-White halo models: comparison with observations
- TASI Lectures on Dark Matter
- Comments on "Modeling Galaxy Halos Using Dark Matter with Pressure"
- Radial structure, inflow & central mass of stationary radiative galaxy clusters
- Decaying dark matter mimicking time-varying dark energy
- Empirical testing of Tsallis' Thermodynamics as a model for dark matter halos
- Dark matter annihilation at cosmological redshifts: possible relic signal from annihilation of weakly interacting massive particles
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- Jeans analysis in energy-momentum-squared gravity
- Dark matter concentrations in galactic nuclei according to polytropic models
- Dark Matter as a Non-Relativistic Bose-Einstein Condensate with Massive Gravitons
- Cosmological perturbations in the CDM-like limit of a polytropic dark matter model
- Coupled DM heating in SCDEW cosmologies
- Quantum gravitational anomaly as a dark matter
- Physical Implications and Updated Observational Constraints of the PAge-like Unified Dark Fluid Model