The 2dF Galaxy Redshift Survey: the amplitudes of fluctuations in the 2dFGRS and the CMB, and implications for galaxy biasing

2001/12/31 by Ofer Lahav, O. Lahav, Sarah L. Bridle +40 · 5 citations
Physics and Astronomy · #Amplitude #Anisotropy #Astronomy #Astronomy and Astrophysical Research #Astrophysics #CMB cold spot #Cosmic background radiation #Cosmic microwave background #Cosmology and Gravitation Theories #Galaxies: Formation, Evolution, Phenomena #Galaxy #Galaxy cluster #Hubble's law #Omega #Physics #Planck #Redshift #Reionization #astro-ph

paper · pdf · doi:10.1046/j.1365-8711.2002.05485.x

published as Mon.Not.Roy.Astron.Soc.333:961,2002 · corrected result for the biasing parameter and minor changes to match the MNRAS accepted version

arxiv created 2002/05/19 · openalex publication_date 2002/07/01 · arxiv updated 2011/03/10 · openalex created_date 2020/11/23 · openalex updated_date 2026/08/05

Abstract

We compare the amplitudes of fluctuations probed by the 2dF Galaxy Redshift Survey (2dFGRS) and by the latest measurements of the cosmic microwave background (CMB) anisotropies. By combining the 2dFGRS and CMB data, we find the linear-theory rms mass fluctuations in 8 h−1 Mpc spheres to be σ8m=0.73±0.05 (after marginalization over the matter density parameter Ωm and three other free parameters). This normalization is lower than the COBE normalization and previous estimates from cluster abundance, but it is in agreement with some revised cluster abundance determinations. We also estimate the scale-independent bias parameter of present-epoch Ls=1.9L∗ APM-selected galaxies to be b(Ls,z=0)=1.10±0.08 on comoving scales of 0.02<k<0.15 h Mpc-1. If luminosity segregation operates on these scales, L∗ galaxies would be almost unbiased, b (L*, z=0)≈0.96. These results are derived by assuming a flat ΛCDM Universe, and by marginalizing over other free parameters and fixing the spectral index n=1 and the optical depth due to reionization τ=0. We also study the best-fitting pair (Ωm, b), and the robustness of the results to varying n and τ. Various modelling corrections can each change the resulting b by 5–15 per cent. The results are compared with other independent measurements from the 2dFGRS itself, and from the Sloan Digital Sky Survey (SDSS), cluster abundance and cosmic shear.

Citations

• The 2dF Galaxy Redshift Survey: the power spectrum and the matter content of the Universe
• Reconstructing Nonlinear Stochastic Bias from Velocity Space Distortions
• The Deuterium to Hydrogen Abundance Ratio toward a Fourth QSO: HS 0105+1619
• Multiple Peaks in the Angular Power Spectrum of the Cosmic Microwave Background: Significance and Consequences for Cosmology
• A measurement of the cosmological mass density from clustering in the 2dF Galaxy Redshift Survey
• Bayesian 'hyper-parameters' approach to joint estimation: the Hubble constant from CMB measurements
• Final Results from theHubble Space TelescopeKey Project to Measure the Hubble Constant
• Weighing Neutrinos with Galaxy Surveys
• The effect of reionization on the COBE normalization
• The 2dF Galaxy Redshift Survey: galaxy luminosity functions per spectral type
• The 2dF Galaxy Redshift Survey: the dependence of galaxy clustering on luminosity and spectral type
• The nature of galaxy bias and clustering

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