Optical depth to reionization from perturbative 21cm clustering

Abstract

The optical depth $\tau$ is the least well determined parameter in the standard model of cosmology, and one whose precise value is important for both understanding reionization and for inferring fundamental physics from cosmological measurements. We forecast how well future epoch of reionization experiments could constraint $\tau$ using a symmetries-based bias expansion that highlights the special role played by anisotropies in the power spectrum on large scales. Given a parametric model for the ionization evolution inspired by the physical behavior of more detailed reionization simulations, we find that future 21cm experiments could place tight constraints on the timing and duration of reionization and hence constraints on $\tau$ that are competitive with proposed, space-based CMB missions provided they can measure $k\approx 0.1h{\text{Mpc}}^{-1}$ with a clean foreground wedge across redshifts spanning the most active periods of reionization, corresponding to ionization fractions $0.2\lesssim x\lesssim 0.8$. Significantly improving upon existing CMB-based measurements with next-generation 21cm surveys would require substantially longer observations ($\sim 5$ years) than standard $\mathcal{O}(1000\text{hour})$ integration times. Precise measurements of smaller scales will not improve constraints on $\tau$ until a better understanding of the astrophysics of reionization is achieved. In the presence of noise and foregrounds even future 21cm experiments will struggle to constrain $\tau$ if the ionization evolution deviates significantly from simple parametric forms.

arXiv commentpublished in JCAP

References in corpus (61)

• The Cosmic Linear Anisotropy Solving System (CLASS) II: Approximation schemes
• Large-Scale Structure of the Universe and Cosmological Perturbation Theory
• Planck 2018 results. I. Overview and the cosmological legacy of Planck
• Cosmology at Low Frequencies: The 21 cm Transition and the High-Redshift Universe
• Constraining the Evolution of the Ionizing Background and the Epoch of Reionization with z ~ 6 Quasars II: A Sample of 19 Quasars
• Large-Scale Galaxy Bias
• 21-cm Tomography of the Intergalactic Medium at High Redshift
• Hydrogen Epoch of Reionization Array (HERA)
• Cosmological Non-Linearities as an Effective Fluid
• The Effective Field Theory of Cosmological Large Scale Structures
• Resumming Cosmological Perturbations via the Lagrangian Picture: One-loop Results in Real Space and in Redshift Space
• Cosmological Parameter Estimation Using 21 cm Radiation from the Epoch of Reionization
• Relative velocity of dark matter and baryonic fluids and the formation of the first structures
• Clustering of dark matter tracers: generalizing bias for the coming era of precision LSS
• What Next-Generation 21 cm Power Spectrum Measurements Can Teach Us About the Epoch of Reionization
• The Evolution of the Intergalactic Medium
• Four Fundamental Foreground Power Spectrum Shapes for 21 cm Cosmology Observations
• A Method for Separating the Physics from the Astrophysics of High-Redshift 21cm Fluctuations
• Radiative transfer simulations of cosmic reionization I: methodology and initial results
• Introducing the THESAN project: radiation-magnetohydrodynamic simulations of the epoch of reionization
• Bias in the Effective Field Theory of Large Scale Structures
• Renormalized Halo Bias
• The Lagrangian-space Effective Field Theory of Large Scale Structures
• First Results from HERA Phase I: Upper Limits on the Epoch of Reionization 21 cm Power Spectrum
• DEMNUni: The clustering of large-scale structures in the presence of massive neutrinos
• A Lagrangian effective field theory
• The Baryon Acoustic Oscillation Broadband and Broad-beam Array: Design Overview and Sensitivity Forecasts
• Reionization and high-redshift galaxies: the view from quasar absorption lines
• Redshift-Space Distortions in Lagrangian Perturbation Theory
• Consistent Modeling of Velocity Statistics and Redshift-Space Distortions in One-Loop Perturbation Theory
• Redshift Space Distortion of the 21cm Background from the Epoch of Reionization I: Methodology Re-examined
• Eliminating the optical depth nuisance from the CMB with 21 cm cosmology
• The Impact of the First Galaxies on Cosmic Dawn and Reionization
• Reconstructing Patchy Reionization from the Cosmic Microwave Background
• The Gaussian streaming model and Lagrangian effective field theory
• Long Dark Gaps in the Ly$\beta$ Forest at $z<6$: Evidence of Ultra Late Reionization from XQR-30 Spectra
• Interpreting LOFAR 21-cm signal upper limits at z~9.1 in the context of high-z galaxy and reionisation observations
• The Aurora radiation-hydrodynamical simulations of reionization: calibration and first results
• Updated design of the CMB polarization experiment satellite LiteBIRD
• The effect of relative velocity and density perturbations between baryons and dark matter on the clustering of galaxies
• Exploring redshift-space distortions in large-scale structure
• Exploring reionisation and high-z galaxy observables with recent multi-redshift MWA upper limits on the 21-cm signal
• The Impact of Foregrounds on Redshift Space Distortion Measurements With the Highly-Redshifted 21 cm Line
• Reconstructing large-scale structure with neutral hydrogen surveys
• Supersonic Relative Velocity Effect on the Baryonic Acoustic Oscillation Measurements
• The observable 21cm signal from reionization may be perturbative
• AMBER: A Semi-numerical Abundance Matching Box for the Epoch of Reionization
• Characterizing the Epoch of Reionization with the small-scale CMB: constraints on the optical depth and physical parameters
• Biased Tracers of Two Fluids in the Lagrangian Picture
• Mitigating the optical depth degeneracy using the kinematic Sunyaev-Zel'dovich effect with CMB-S4
• Background reionization history from omniscopes
• Beware of Fake $\nu$s: The Effect of Massive Neutrinos on the Nonlinear Evolution of Cosmic Structure
• Measuring the growth of structure with intensity mapping surveys
• Signatures of Cosmic Reionization on the 21cm 2- and 3-point Correlation Function I: Quadratic Bias Modeling
• The Ly$\alpha$ forest flux correlation function: a perturbation theory perspective
• SCORCH. II. Radiation-Hydrodynamic simulations of reionization with varying radiation escape fractions
• Statistical analysis of the causes of excess variance in the 21 cm signal power spectra obtained with the Low-Frequency Array
• An Effective Bias Expansion for 21 cm Cosmology in Redshift Space
• Out-of-Core Hydrodynamic Simulations for Cosmological Applications
• Parametrizing the Reionization History with the Redshift Midpoint, Duration, and Asymmetry
• The HI Bias during the Epoch of Reionization

Cited by in corpus (1)

• Improved Constraints on the 21 cm EoR Power Spectrum and the X-Ray Heating of the IGM with HERA Phase I Observations