Model ΛCDM

In Cosmologie the model ΛCDM (to pronounce “Lambda CDM”, for Standard Cold Dark Matter ) indicates a cosmological Modèle representing a homogeneous universe and isotropic, whose space Courbure is null, and who contains black Matière and black energy in addition to the ordinary matter. The Greek letter Λ is usually the symbol of the cosmological Constante, which is the simplest form of black energy.

Such a model (2006) is regarded today as models it cosmological simplest being able to describe the observable Univers. It is at the base of the standard Modèle of cosmology. It supplanted the Modèle SCDM, identical if it is not that it does not have black energy, in the current of the Années 1990.

The motivation of this type of model comes from the combination of several observations which force some cosmological parameters:

the indirect detection of black Matter, by its gravitational influence within the Galaxy S and of the Galaxy cluster;
the estimate of the density of this black matter, which is lower than the Densité criticizes universe;
constraints on the space Curve of the universe which indicates that the total density of the universe is very close to the critical density;
observation of the Acceleration of the expansion of the universe by the study of the Distance from luminosity of the Supernova E of the Ia type, which imply the existence of black energy.

The combination of these constraints makes necessary the presence of matter black, as well as the addition of another form of matter, black energy, having a repulsive effect on the expansion of the universe.

See too

standard Modèle of cosmology
black Matière
black Énergie
Densité criticizes
Table of the astrophysical constants

References

Works specialized on cosmology

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