Towards physics responsible for large-scale Lyman-$\alpha$ forest bias parameters

Abstract

Using a series of carefully constructed numerical experiments based on hydrodynamic cosmological SPH simulations, we attempt to build an intuition for the relevant physics behind the large scale density ($b_{\delta }$) and velocity gradient ($b_{\eta }$) biases of the Lyman-$\alpha$ forest. Starting with the fluctuating Gunn-Peterson approximation applied to the smoothed total density field in real-space, and progressing through redshift-space with no thermal broadening, redshift-space with thermal broadening and hydrodynamicaly simulated baryon fields, we investigate how approximations found in the literature fare. We find that Seljak's 2012 analytical formulae for these bias parameters work surprisingly well in the limit of no thermal broadening and linear redshift-space distortions. We also show that his $b_{\eta }$ formula is exact in the limit of no thermal broadening. Since introduction of thermal broadening significantly affects its value, we speculate that a combination of large-scale measurements of $b_{\eta }$ and the small scale flux PDF might be a sensitive probe of the thermal state of the IGM. We find that large-scale biases derived from the smoothed total matter field are within 10-20\% to those based on hydrodynamical quantities, in line with other measurements in the literature.

References in corpus (12)

• Baryon Acoustic Oscillations in the Lyα forest of BOSS DR11 quasars
• Cosmological parameters from combining the Lyman-alpha forest with CMB, galaxy clustering and SN constraints
• Baryon Acoustic Oscillations in the Ly-α forest of BOSS quasars
• Clustering of dark matter tracers: generalizing bias for the coming era of precision LSS
• Can sterile neutrinos be the dark matter?
• Evidence for dark matter interactions in cosmological precision data?
• Minimally Parametric Power Spectrum Reconstruction from the Lyman-alpha Forest
• Constraint on neutrino masses from SDSS-III/BOSS Ly$\alpha$ forest and other cosmological probes
• The Non-Linear Power Spectrum of the Lyman Alpha Forest
• Scale-dependent bias in the BAO-scale intergalactic neutral hydrogen
• The Acoustic Peak in the Lyman Alpha Forest
• Optimizing BAO measurements with non-linear transformations of Lyman-alpha forest

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• The Ly$\alpha$ forest flux correlation function: a perturbation theory perspective
• The triply-ionized carbon forest from eBOSS: cosmological correlations with quasars in SDSS-IV DR14
• Response approach to the squeezed-limit bispectrum: application to the correlation of quasar and Lyman-$\alpha$ forest power spectrum
• Neutrino mass bounds from confronting an effective model with BOSS Lyman-alpha data
• A hierarchical field-level inference approach to reconstruction from sparse Lyman-$\alpha$ forest data
• First Detection of Cosmic Microwave Background Lensing and Lyman-α Forest Bispectrum
• Quintessential Scale Dependence from Separate Universe Simulations
• Mapping Lyman-alpha forest three-dimensional large scale structure in real and redshift space
• Measurement of Void Bias Using Separate Universe Simulations
• The Lyman-$\alpha$ power spectrum - CMB lensing convergence cross-correlation
• Constraining dark energy using the cross correlations of weak lensing with post-reionization probes of neutral hydrogen
• An Analytically Tractable Marked Power Spectrum
• Lyman-alpha power spectrum as a probe of modified gravity
• Modeling the Cosmological Lyman-$\alpha$ Forest at the Field Level