Scale-dependent bias in the BAO-scale intergalactic neutral hydrogen

Abstract

I discuss fluctuations in the neutral hydrogen (HI) density of the z~2.3 intergalactic medium and show that their relation to cosmic overdensity is strongly scale-dependent. This behaviour arises from a linearized version of the well-known "proximity effect", in which bright sources suppress atomic hydrogen density. Using a novel, systematic and detailed linear-theory radiative transfer calculation, I demonstrate how HI density consequently anti-correlates with total matter density when averaged on scales exceeding the Lyman-limit mean-free-path. The radiative transfer thumbprint is highly distinctive and should be measurable in the Lyman-alpha forest. Effects extend to sufficiently small scales to generate significant distortion of the correlation function shape around the baryon acoustic oscillation peak, although the peak location shifts only by 1.2 percent for a mean source bias of b_j=3. The distortion changes significantly with b_j and other astrophysical parameters; measuring it should provide a helpful observational constraint on the nature of ionizing photon sources in the near future.

Accepted for publication in PRD. No change in results. Updated default parameters and expanded discussion

References in corpus (10)

• An Observational Determination of the Bolometric Quasar Luminosity Function
• Observational constraints on Cosmic Reionization
• A New Calculation of the Ionizing Background Spectrum and the Effects of HeII Reionization
• Baryon Acoustic Oscillations in the Ly-α forest of BOSS quasars
• Damped Lyman Alpha Systems in Galaxy Formation Simulations
• How cold is cold dark matter? Small scales constraints from the flux power spectrum of the high-redshift Lyman-alpha forest
• Possible evidence for an inverted temperature-density relation in the intergalactic medium from the flux distribution of the Lyman-alpha forest
• The Acoustic Peak in the Lyman Alpha Forest
• Fluctuations in the Ionizing Background During and After Helium Reionization
• A Linear Perturbation Theory of Inhomogeneous Reionization

Cited by in corpus (11)

• Baryon acoustic oscillations from the complete SDSS-III Ly$\alpha$-quasar cross-correlation function at $z=2.4$
• Self-Consistent Modeling of Reionization in Cosmological Hydrodynamical Simulations
• An EFT description of galaxy intrinsic alignments
• Biased Tracers of Two Fluids in the Lagrangian Picture
• Impact of inhomogeneous reionization on the Lyman-α forest
• First Detection of Cosmic Microwave Background Lensing and Lyman-α Forest Bispectrum
• Making sense of the local Galactic escape speed estimates in direct dark matter searches
• The impact of temperature fluctuations on the large-scale clustering of the Ly$\alpha$ forest
• Extracting the astrophysics of reionization from the Ly$\alpha$ forest power spectrum: a first forecast
• The Linear Perturbation Theory of Reionization in Position-Space: Cosmological Radiative Transfer Along the Light-Cone
• The effect of ionizing background fluctuations on the spatial correlations of high redshift Ly$\alpha$-emitting galaxies