Constraints on Cosmological Parameters from the Lyman-alpha Forest Power Spectrum and COBE-DMR

Abstract

We combine COBE-DMR measurements of cosmic microwave background anisotropy with a recent measurement of the mass power spectrum at redshift z=2.5 from Lya forest data to derive constraints on cosmological parameters and test the inflation+CDM scenario of structure formation. By treating the inflationary spectral index n as a free parameter, we can find successful fits to the COBE and Lya forest constraints in Omega_m=1 models with and without massive neutrinos and in low-Omega_m models with and without a cosmological constant. Within each class of model, the combination of COBE and the Lya forest P(k) constrains a parameter combination of the form (Omega_m h^a n^b Omega_b^c), with different indices for each case. This new constraint breaks some of the degeneracies in cosmological parameter determinations from other measurements. The Lya forest P(k) provides the first measurement of the slope of the linear mass power spectrum on ~Mpc scales, and it confirms a basic prediction of the inflationary CDM scenario: a nearly scale-invariant spectrum of primeval fluctuations (n~1) that bends towards k^{n-4} on small scales. Considering additional observational data, we find that COBE-normalized, Omega_m=1 models that match the Lya forest P(k) do not match the observed masses of rich galaxy clusters and that a low-Omega_m model with a cosmological constant provides the best overall fit, even without the direct evidence for cosmic acceleration from supernovae. Modest improvements in the Lya forest P(k) measurement could greatly restrict the allowable region of parameter space for CDM models, constrain the contribution of tensor fluctuations to CMB anisotropy, and achieve a more stringent test of the current consensus model of structure formation.

arXiv comment26 pages, 6 figs, ApJ, in press (10/01). New version corrects some numerical results for Lambda-CDM models, updates discussion in light of new observational developments (especially CMB). Main conclusions unchanged

References in corpus (44)

• Observational Evidence from Supernovae for an Accelerating Universe and a Cosmological Constant
• Measurements of Omega and Lambda from 42 High-Redshift Supernovae
• A Line of Sight Approach to Cosmic Microwave Background Anisotropies
• 4-Year COBE DMR Cosmic Microwave Background Observations: Maps and Basic Results
• The Cosmic Triangle: Revealing the State of the Universe
• Using the Evolution of Clusters to Constrain Omega
• Cluster Abundance Constraints on Quintessence Models
• Power Spectra for Cold Dark Matter and its Variants
• Reconstructing the linear power spectrum of cosmological mass fluctuations
• Cosmic Background Anisotropies in CDM Cosmology
• Biasing and Hierarchical Statistics in Large-scale Structure
• Gravitational Collapse of Small-Scale Structure as the Origin of the Lyman Alpha Forest
• The Lyman-alpha Forest in the Cold Dark Matter Model
• The Four-Year COBE Normalization and Large-Scale Structure
• Recovery of the Power Spectrum of Mass Fluctuations from Observations of the Lyman-alpha Forest
• A Measurement of the Angular Power Spectrum of the CMB from l = 100 to 400
• The Deuterium Abundance Towards Q1009+2956
• The Physics of Microwave Background Anisotropies
• The Observed Probability Distribution Function, Power Spectrum, and Correlation Function of the Transmitted Flux in the Lyman-alpha Forest
• Evolution of Structure in the Intergalactic Medium and the Nature of the Ly-alpha Forest
• A Multi-Species Model for Hydrogen and Helium Absorbers in Lyman-Alpha Forest Clouds
• The Power Spectrum of Mass Fluctuations Measured from the Lyman-alpha Forest at Redshift z=2.5
• The Intracluster Gas Fraction in X-ray Clusters : Constraints on the Clustered Mass Density
• A measurement of Omega from the North American test flight of BOOMERANG
• Cosmic Microwave Background Probes Models of Inflation
• Constraints on the Effects of Locally-biased Galaxy Formation
• The Statistics of Density Peaks and the Column Density Distribution of the Lyman-Alpha Forest
• Small-Scale Cosmic Microwave Background Anisotropies as a Probe of the Geometry of the Universe
• Integral Solution for the Microwave Background Anisotropies in Non-fl at Universes
• Cosmological Limits on the Neutrino Mass from the Lya Forest
• Eulerian bias and the galaxy density field
• Correlations in the Spatial Power Spectrum Inferred from Angular Clustering: Methods and Application to APM
• Linear Power Spectra in Cold+Hot Dark Matter Models: Analytical Approximations and Applications
• Locally Biased Galaxy Formation and Large Scale Structure
• Maximum Likelihood Estimates of the Two- and Three-Dimensional Power Spectra of the APM Galaxy Survey
• The Neutral Hydrogen Column Density towards Q1937--1009 from the Unabsorbed Intrinsic Continuum in the Lyman-$\alpha$ Forest
• Large-Scale Power Spectrum and Cosmological Parameters from SFI Peculiar Velocities
• Cosmological Density and Power Spectrum from Peculiar Velocities: Nonlinear Corrections and PCA
• Cosmological parameters from cluster abundances, CMB and IRAS
• Closing in on Omega_0: The Amplitude of Mass Fluctuations from Galaxy Clusters and the Lyman-alpha Forest
• Tensor Anisotropies in an Open Universe
• The build-up of halos within Press-Schechter theory
• Non-Nucleosynthetic Constraints on the Baryon Density and Other Cosmological Parameters
• Large-scale structure formation for power spectra with broken scale invariance

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• Non-linearities in the Lyman-$\alpha$ forest and in its cross-correlation with dark matter halos
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