Early-matter-like dark energy and the cosmic microwave background

Journal Article · Fri Jan 01 04:00:00 EST 2016 · Journal of Cosmology and Astroparticle Physics

DOI:https://doi.org/10.1088/1475-7516/2016/01/021· OSTI ID:22525074

Aurich, R.

Early-matter-like dark energy is defined as a dark energy component whose equation of state approaches that of cold dark matter (CDM) at early times. Such a component is an ingredient of unified dark matter (UDM) models, which unify the cold dark matter and the cosmological constant of the ΛCDM concordance model into a single dark fluid. Power series expansions in conformal time of the perturbations of the various components for a model with early-matter-like dark energy are provided. They allow the calculation of the cosmic microwave background (CMB) anisotropy from the primordial initial values of the perturbations. For a phenomenological UDM model, which agrees with the observations of the local Universe, the CMB anisotropy is computed and compared with the CMB data. It is found that a match to the CMB observations is possible if the so-called effective velocity of sound c{sub eff} of the early-matter-like dark energy component is very close to zero. The modifications on the CMB temperature and polarization power spectra caused by varying the effective velocity of sound are studied.

• OSTI ID: 22525074
• Journal Information: Journal of Cosmology and Astroparticle Physics, Journal Name: Journal of Cosmology and Astroparticle Physics Journal Issue: 01 Vol. 2016; ISSN 1475-7516
• Country of Publication: United States
• Language: English

Related Subjects

79 ASTRONOMY AND ASTROPHYSICS
ANISOTROPY
COMPARATIVE EVALUATIONS
COSMOLOGICAL CONSTANT
DISTURBANCES
ENERGY SPECTRA
EQUATIONS OF STATE
EXPANSION
FLUIDS
NONLUMINOUS MATTER
POLARIZATION
RELICT RADIATION
SOUND WAVES
UNIVERSE
VELOCITY