Phenomenological models for Unified Dark Matter with fast transition

Abstract

A fast transition between a standard matter-like era and a late $\Lambda$ cold dark matter ($\Lambda$CDM)-like epoch (or more in general, a CDM+DE era), generated by a single Unified Dark Matter component, can provide a new interesting paradigm in the context of general relativity, alternative to $\Lambda$CDM itself or other forms of DE or modified gravity theories invoked to explain the observed acceleration of the Universe. UDM models with a fast transition have interesting features, leading to measurable predictions, thus they should be clearly distinguishable from $\Lambda$CDM (and alternatives) through observations. Here we look at different ways of prescribing phenomenological UDM models with fast transition, then focusing on a particularly simple model. We analyse the viability of this model by studying features of the background model and properties of the adiabatic UDM perturbations, which depend on the effective speed of sound and the functional form of the Jeans scale. As a result, theoretical constraints on the parameters of the models are found that allow for a behaviour compatible with observations.

11 pages, 9 figures. Matches published version in MNRAS. arXiv admin note: text overlap with arXiv:1008.0614 by other authors

References in corpus (15)

• Unified cosmic history in modified gravity: from F(R) theory to Lorentz non-invariant models
• Modified Gravity and Cosmology
• Dark Energy
• Modified gravity models of dark energy
• Does Bulk Viscosity Create a Viable Unified Dark Matter Model?
• Gauge-invariant analysis of perturbations in Chaplygin gas unified models of dark matter and dark energy
• Unified Dark Matter in Scalar Field Cosmologies
• Cosmological bounds on the equation of state of dark matter
• $\Lambda \alpha$DM: Observational constraints on unified dark matter with constant speed of sound
• Affine equation of state from quintessence and k-essence fields
• Cosmo-dynamics and dark energy with a quadratic EoS: anisotropic models, large-scale perturbations and cosmological singularities
• Cosmological tachyon condensation
• ISW effect in Unified Dark Matter Scalar Field Cosmologies: an analytical approach
• Affine parameterization of the dark sector: costraints from WMAP5 and SDSS
• Halos of Unified Dark Matter Scalar Field

Cited by in corpus (18)

• Resolving the $H_0$ tension with diffusion
• Unified Superfluid Dark Sector
• Implications of the Cosmic Birefringence Measurement for the Axion Dark Matter Search
• Analysing dissipative effects in the $\Lambda$CDM model
• Cosmological perturbation theory in Generalized Einstein-Aether models
• Constraints on a decomposed dark fluid with constant adiabatic sound speed by jointing the geometry test and growth rate after Planck data
• Bayesian analysis of a Unified Dark Matter model with transition: can it alleviate the $H_0$ tension?
• Cosmological constraints on a unified dark matter-energy scalar field model with fast transition
• A thermodynamic point of view on dark energy models
• Thermodynamics of the unified dark fluid with fast transition
• Cosmological constrains on fast transition Unified Dark Energy/Matter models
• Observational constraints to a unified cosmological model
• Analytic Study of Cosmological Perturbations in a Unified Model of Dark Matter and Dark Energy with a Sharp Transition
• Dark Coincidences: Small-Scale Solutions with Refracted Gravity and MOND
• WIMP dark matter in bulk viscous non-standard cosmologies
• Early-Matter-Like Dark Energy and the Cosmic Microwave Background
• FIMP Dark Matter in bulk viscous non-standard cosmologies
• Refracted Gravity Solutions from Small to Large Scales