Fingerprinting dark energy. II. Weak lensing and galaxy clustering tests

Journal Article · Mon Nov 15 04:00:00 EST 2010 · Physical Review. D, Particles Fields

DOI:https://doi.org/10.1103/PHYSREVD.82.103535· OSTI ID:21509918

Sapone, Domenico ^[1]; Kunz, Martin ^[2]; Amendola, Luca ^[3]

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1. Departamento de Fisica Teorica and Instituto de Fisica Teorica, Universidad Autonoma de Madrid IFT-UAM/CSIC, Cantoblanco, Madrid (Spain)
2. Departement de Physique Theorique, Universite de Geneve, 24 quai Ernest Ansermet, CH-1211 Geneve 4 (Switzerland)
3. University of Heidelberg, Philosophenweg 16, 69120 Heidelberg (Germany)

The characterization of dark energy is a central task of cosmology. To go beyond a cosmological constant, we need to introduce at least an equation of state and a sound speed and consider observational tests that involve perturbations. If dark energy is not completely homogeneous on observable scales, then the Poisson equation is modified and dark matter clustering is directly affected. One can then search for observational effects of dark energy clustering using dark matter as a probe. In this paper we exploit an analytical approximate solution of the perturbation equations in a general dark energy cosmology to analyze the performance of next-decade large-scale surveys in constraining equation of state and sound speed. We find that tomographic weak lensing and galaxy redshift surveys can constrain the sound speed of the dark energy only if the latter is small, of the order of c{sub s} < or approx. 0.01 (in units of c). For larger sound speeds the error grows to 100% and more. We conclude that large-scale structure observations contain very little information about the perturbations in canonical scalar field models with a sound speed of unity. Nevertheless, they are able to detect the presence of cold dark energy, i.e. a dark energy with nonrelativistic speed of sound.

• OSTI ID: 21509918
• Journal Information: Physical Review. D, Particles Fields, Journal Name: Physical Review. D, Particles Fields Journal Issue: 10 Vol. 82; ISSN PRVDAQ; ISSN 0556-2821
• Country of Publication: United States
• Language: English

Related Subjects

72 PHYSICS OF ELEMENTARY PARTICLES AND FIELDS
79 ASTRONOMY AND ASTROPHYSICS
APPROXIMATIONS
CALCULATION METHODS
COSMOLOGICAL CONSTANT
COSMOLOGY
DIFFERENTIAL EQUATIONS
DISTURBANCES
EQUATIONS
EQUATIONS OF STATE
GALAXIES
GALAXY CLUSTERS
MATHEMATICAL SOLUTIONS
MATTER
NONLUMINOUS MATTER
PARTIAL DIFFERENTIAL EQUATIONS
PERTURBATION THEORY
POISSON EQUATION
RED SHIFT
SCALAR FIELDS
SOUND WAVES
VELOCITY