Lambda CDM model

The evolution of the universe and its horizons (Ω _R = 0.00005, Ω _M = 0.317, Ω _Λ = 0.683, Ω _M + Ω _Λ = 1):
Particle Horizon, Event Horizon, Light Cone, Hubble Radius.

The ΛCDM model or Lambda CDM model is a cosmological model that describes the development of the universe since the Big Bang with just a few - in the basic form six - parameters . Since it is the simplest model that is in good agreement with cosmological measurements, it is also called the Standard Model of Cosmology .

The Greek letter lambda (Λ) stands for the cosmological constant , CDM for cold dark matter ( cold dark matter ).

The Lambda CDM model is in good agreement with the three main classes of observations that tell us about the early universe:

• the measurement of the anisotropy of the background radiation ,
• the determination of the expansion rate and its change over time by observing supernovae in distant galaxies and
• the data on superstructures in the cosmos .

The universe is assumed to be globally flat (not curved ), the energy shares relative to the critical density are then also relative to the actual total energy density and the relative share of dark energy results in (69.1 ± 0.6)%. Today's total energy density is 8.62 · 10 ⁻²⁷  kg / m ³ , the redshift z , which corresponds to the age of reionization, is 11.37. The age of the universe is determined to be 13.8 billion years.

The six parameters of the ΛCDM model

size	amount	description
${\displaystyle H_{0}}$	${\displaystyle (67{,}8\pm 0{,}9)\;\mathrm {km} \,\mathrm {s} ^{-1}\mathrm {Mpc} ^{-1}}$	Hubble constant
${\displaystyle \Omega _{b}}$	${\displaystyle 0{,}044\pm 0{,}001\,7}$	Share of baryonic matter in the total energy density (including dark matter and dark energy)
${\displaystyle \Omega _{m}}$	${\displaystyle 0{,}308\pm 0{,}012}$	Total share of (baryonic and dark) matter in the total energy density (including dark energy)
	${\displaystyle 0{,}30\pm 0{,}04}$
	${\displaystyle 0{,}267\pm 0{,}019}$
${\displaystyle \tau }$	${\displaystyle 0{,}066\pm 0{,}016}$	Optical thickness up to the age of reionization
${\displaystyle A_{s}}$	${\displaystyle (2{,}215\pm 0{,}13)\cdot 10^{-9}}$	Curvature fluctuation amplitude of the scalar component of the original fluctuations
${\displaystyle n_{s}}$	${\displaystyle 0{,}968\pm 0{,}006}$	spectral index of the scalar component of the original fluctuations

literature

• David N. Spergel et al. a. (WMAP collaboration): Wilkinson Microwave Anisotropy Probe (WMAP) three year results: implications for cosmology.
• Rafael Rebolo et al. a. (VSA collaboration): Cosmological parameter estimation using Very Small Array data out to l = 1500 . In: Monthly Notices of the Royal Astronomical Society . Oxford 353.2004, No. 3, pp. 747-759, arxiv : astro-ph / 0402466 . ISSN  0035-8711

Web links

• The cosmological standard model on the test bench . (PDF) In: Spectrum of Science , August 2010 (10 pages)
• Planck 2013 results. XVI. Cosmological parameters : Planck Collaboration, March 2013 (69 pages) arxiv : 1303.5076

Individual evidence

1. ^ Austin Joyce et al .: Beyond the Cosmological Standard Model . arxiv : 1407.0059
2. ↑ ^{a b c d e} Planck 2015 Results. XIII. Cosmological parameter , arxiv : 1502.01589v3 .
3. ↑ M. Tegmark et al. a. ( SDSS collaboration): Cosmological Parameters from SDSS and WMAP . In: Physical Review D , Melville 69, 2004, p. 103501, arxiv : astro-ph / 0310723 , ISSN  0556-2821
4. ↑ David N. Spergel et al. a. (WMAP collaboration): First year Wilkinson Microwave Anisotropy Probe (WMAP) observations: determination of cosmological parameters . In: The astrophysical journal. Supplement series. Chicago 148.2003, p. 175, arxiv : astro-ph / 0302209v3 . ISSN  0067-0049