Using idealized synthetic data, knowing the true continuum in Lyα forest auto- and cross-correlations reduces uncertainties on the AP parameter and Ω_m by ~10%, with extension to 240 h^{-1}Mpc scales adding up to ~15% further improvement equivalent to a 40% larger survey area.
Scale-dependent bias in the BAO-scale intergalactic neutral hydrogen
4 Pith papers cite this work. Polarity classification is still indexing.
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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.
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DESI measures BAO from the Lyα forest at z_eff=2.33, reporting H(z) = (239.2 ± 4.8) (147.09 Mpc/rd) km/s/Mpc and DM(z) = (5.84 ± 0.14) (rd/147.09 Mpc) Gpc.
DESI DR2 delivers 0.65% precision BAO measurements from the LyA forest at z_eff=2.33, with D_H/r_d = 8.632 ± 0.098 ± 0.026 and D_M/r_d = 38.99 ± 0.52 ± 0.12.
DESI will target luminous red galaxies to z=1, emission-line galaxies to z=1.7, quasars for tracers and Ly-alpha forest at 2.1<z<3.5, plus a bright galaxy survey, to obtain more than 30 million redshifts for BAO and matter power spectrum measurements.
citing papers explorer
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Probing the limits of cosmological information from the Lyman-$\alpha$ forest 2-point correlation functions
Using idealized synthetic data, knowing the true continuum in Lyα forest auto- and cross-correlations reduces uncertainties on the AP parameter and Ω_m by ~10%, with extension to 240 h^{-1}Mpc scales adding up to ~15% further improvement equivalent to a 40% larger survey area.
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DESI 2024 IV: Baryon Acoustic Oscillations from the Lyman Alpha Forest
DESI measures BAO from the Lyα forest at z_eff=2.33, reporting H(z) = (239.2 ± 4.8) (147.09 Mpc/rd) km/s/Mpc and DM(z) = (5.84 ± 0.14) (rd/147.09 Mpc) Gpc.
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DESI DR2 Results I: Baryon Acoustic Oscillations from the Lyman Alpha Forest
DESI DR2 delivers 0.65% precision BAO measurements from the LyA forest at z_eff=2.33, with D_H/r_d = 8.632 ± 0.098 ± 0.026 and D_M/r_d = 38.99 ± 0.52 ± 0.12.
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The DESI Experiment Part I: Science,Targeting, and Survey Design
DESI will target luminous red galaxies to z=1, emission-line galaxies to z=1.7, quasars for tracers and Ly-alpha forest at 2.1<z<3.5, plus a bright galaxy survey, to obtain more than 30 million redshifts for BAO and matter power spectrum measurements.