An improved measurement of the flux distribution of the Ly-alpha forest in QSO absorption spectra: the effect of continuum fitting, metal contamination and noise properties

Abstract

We have performed an extensive Voigt profile analysis of the neutral hydrogen (HI) and metal absorption present in a sample of 18 high resolution, high signal-to-noise QSO spectra observed with VLT/UVES. We use this analysis to separate the metal contribution from the HI absorption and present an improved measurement of the flux probability distribution function (PDF) due to HI absorption alone at <z> = 2.07, 2.52, and 2.94. The flux PDF is sensitive to the continuum fit in the normalised flux range 0.8 < F < 1.0 and to metal absorption at 0.2 < F < 0.8. Our new measurements of the flux PDF due to HI absorption alone are systematically lower at 0.2 < F < 0.8 by up to 30% compared to the widely used measurement of McDonald et al. (2000), based on a significantly smaller sample of Keck/HIRES data. This discrepancy is probably due to a combination of our improved removal of the metal absorption and cosmic variance, since variations in the flux PDF between different lines-of-sight are large. The HI effective optical depth at 1.7 < z < 4 is best fit with a single power law, (0.0023 +-0.0007) (1+z)^(3.65 +- 0.21), in good agreement with previous measurements from comparable data. As also found previously, the effect of noise on the flux distribution is not significant in high resolution, high signal-to-noise data.

arXiv commentAccepted 2007 September 3 for publication on MNRAS, 21 pages, 13 figures and 6 tables. Data and high-resolution versions of Figs. 2, 3 and 4 and of the paper are available on http://adlibitum.oat.ts.astro.it/viel/PDF/

References in corpus (38)

• Composite Quasar Spectra From the Sloan Digital Sky Survey
• Constraining the Evolution of the Ionizing Background and the Epoch of Reionization with z ~ 6 Quasars II: A Sample of 19 Quasars
• The Low Redshift Lyman Alpha Forest in Cold Dark Matter Cosmologies
• Gravitational Collapse of Small-Scale Structure as the Origin of the Lyman Alpha Forest
• The Lyman-alpha Forest Power Spectrum from the Sloan Digital Sky Survey
• Towards a Precise Measurement of Matter Clustering: Lyman-alpha Forest Data at Redshifts 2-4
• Recovery of the Power Spectrum of Mass Fluctuations from Observations of the Lyman-alpha Forest
• The Opacity of the Lyman Alpha Forest and Implications for Omega_{baryon} and the Ionizing Background
• P3M-SPH simulations of the Lyman-alpha Forest
• The Lyman Alpha Forest from Gravitational Collapse in the CDM+Lambda Model
• The Observed Probability Distribution Function, Power Spectrum, and Correlation Function of the Transmitted Flux in the Lyman-alpha Forest
• Inferring the dark matter power spectrum from the Lyman-alpha forest in high-resolution QSO absorption spectra
• The Evolution of Optical Depth in the Ly-alpha Forest: Evidence Against Reionization at z~6
• The Distribution of Column Densities and b Values in the Lyman-Alpha Forest
• The Lyman-alpha forest opacity and the metagalactic hydrogen ionization rate at z~2-4
• The Evolution of the Intergalactic Medium Transmission to Redshift Six
• Intrinsic Properties of the <z>=2.7 Lyman Alpha Forest from Keck Spectra of QSO HS 1946+7658
• The physical properties of the Ly-Alpha forest at z > 1.5
• Spectral Analysis of the Lyman Alpha Forest in a Cold Dark Matter Cosmology
• The power spectrum of the flux distribution in the Lyman-alpha forest of a Large sample of UVES QSO Absorption Spectra (LUQAS)
• The Lyman-Alpha Forest at 1.5 < z < 4
• Resolving the Lyman-alpha Forest
• Cosmological constraints from the CMB and Ly-alpha forest revisited
• Properties of High-Redshift Lyman Alpha Clouds I. Statistical Analysis of the SSG Quasars
• Cosmological parameters sigma_8, the baryon density, and the UV background intensity from a calibrated measurement of H I Lyman-alpha absorption at z = 1.9
• The H I opacity of the intergalactic medium at redshifts 1.6 < z < 3.2
• A feature at z ~ 3.2 in the evolution of the Ly-alpha forest optical depth
• The Lyman-alpha forest and WMAP year three
• The enrichment history of the intergalactic medium: O VI in Ly-alpha forest systems at redshift z ~ 2
• A Concordance Model of the Lyman-alpha Forest at z = 1.95
• The Evolution of Lyman alpha Absorbers in the Redshift Range 0.5<z<1.9
• Hydrodynamical simulations of the Lyman-Alpha forest: data comparisons
• Tightening Constraints from the Lyman Alpha Forest with the Flux Probability Distribution Function
• The Probability Distribution of the Lya transmitted flux from a sample of SDSS quasars
• The effect of (strong) discrete absorption systems on the lyman alpha forest flux power spectrum
• The associated system of HE2347-4342
• Joint modeling of the probability distribution and power spectrum of the Lya forest: comparison with observations at z=3
• High-Resolution Spectroscopy from 3050 to 10000 A of the HDF-S QSO J2233-606 with UVES at the ESO VLT

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