2002/12/13 by Licia Verde, Alan F. Heavens, Alan Heavens +7
Physics and Astronomy · #Astronomy and Astrophysical Research #Astrophysics (astro-ph) #Cosmology and Gravitation Theories #FOS: Physical sciences #Galaxies: Formation, Evolution, Phenomena #astro-ph
paper · pdf · doi:10.48550/arxiv.astro-ph/0212311
Proceedings of XXXVIIth Rencontres de Moriond, March 16-23, 2002
arxiv created 2002/12/13 · openalex publication_date 2002/12/13 · arxiv updated 2009/12/01 · openalex created_date 2016/06/24 · openalex updated_date 2026/07/28
By studying the bispectrum of the galaxy distribution in the 2dF galaxy redhsift survey (2dFGRS), we have shown that 2dFGRS galaxies are unbiased tracers of the mass distribution. This allows us the break the degeneracy intrinsic to power spectrum studies, between the matter density parameter Omegam and the bias parameter b, and to obtain an accurate measurement of Omegam: Omega_m,zeff=0.27 ± 0.06, a measurement obtained from the 2dFGRS alone, independently from other data sets. This result has to be interpreted as Omegam at the effective redshift of the survey zeff=0.17. Extrapolated at z=0 we obtain Omegam=0.2 ± 0.06 for the LCDM model. This constraint on the matter density parameter when combined with cosmic microwave background constraints on the flatness of the Universe, show firm evidence that the Universe is dominated by a vacuum energy component.