The subtlety of Ly-a photons: changing the expected range of the 21-cm signal

Abstract

We present the evolution of the 21-cm signal from cosmic dawn and the epoch of reionization (EoR) in an upgraded model including three subtle effects of Ly-a radiation: Ly-a heating, CMB heating (mediated by Ly-a photons), and multiple scattering of Ly-a photons. Taking these effects into account we explore a wide range of astrophysical models and quantify the impact of these processes on the global 21-cm signal and its power spectrum at observable scales and redshifts. We find that, in agreement with the literature, Ly-a and CMB heating raise the gas temperature by up to $\mathcal{O}(100)$ degrees in models with weak X-ray heating and, thus, suppress the predicted 21-cm signals. Varying the astrophysical parameters over broad ranges, we find that in the upgraded model the absorption trough of the global signal reaches a lowest floor of $-165$ mK at redshifts $z\approx 15-19$. This is in contrast with the predictions for a pure adiabatically cooling Universe, for which the deepest possible absorption is a monotonically decreasing function of cosmic time and is $-178$ mK at $z=19$ and $-216$ mK at $z=15$, dropping to even lower values at lower redshifts (e.g. $-264$ mK at $z=10$). With the Ly-a and CMB heating included we also observe a strong suppression in the low-redshift power spectra, with the maximum possible power (evaluated over the ensemble of models) attenuated by a factor of $6.6$ at $z=9$ and $k=0.1$ Mpc${}^{-1}$. Finally, we find that at high redshifts corresponding to cosmic dawn, the heating terms have a subdominant effect while multiple scattering of Ly-a photons is important, leading to an amplification of the power spectrum by a factor of $\sim 2-5$.

References in corpus (16)

• Improved upper limits on the 21-cm signal power spectrum of neutral hydrogen at $\mathbf{z}\approx 9.1$ from LOFAR
• 21CMMC: an MCMC analysis tool enabling astrophysical parameter studies of the cosmic 21 cm signal
• Deep multi-redshift limits on Epoch of Reionisation 21cm Power Spectra from Four Seasons of Murchison Widefield Array Observations
• Signature of Excess Radio Background in the 21-cm Global Signal and Power Spectrum
• The simulated 21 cm signal during the epoch of reionization : full modeling of the Ly-alpha pumping
• The Scattering of Lyman-series Photons in the Intergalactic Medium
• Lyman-alpha radiative transfer during the Epoch of Reionization: contribution to 21-cm signal fluctuations
• High-redshift radio galaxies: a potential new source of 21-cm fluctuations
• The rich complexity of 21-cm fluctuations produced by the first stars
• Heating and cooling of the intergalactic medium by resonance photons
• Modelling the observed luminosity function and clustering evolution of Lyman-$\alpha$ emitters: growing evidence for late reionization
• Lyman-$\alpha$ coupling and heating at Cosmic Dawn
• Detecting Early Galaxies Through Their 21-cm Signature
• The Spin-Resolved Atomic Velocity Distribution and 21-cm Line Profile of Dark-Age Gas
• Lyalpha heating and its impact on early structure formation
• The impact of Lyman-$\alpha$ emission line heating and cooling on the cosmic dawn 21-cm signal

Cited by in corpus (53)

• Improved Constraints on the 21 cm EoR Power Spectrum and the X-Ray Heating of the IGM with HERA Phase I Observations
• HERA Phase I Limits on the Cosmic 21-cm Signal: Constraints on Astrophysics and Cosmology During the Epoch of Reionization
• Constraining primordial black holes as dark matter using the global 21-cm signal with X-ray heating and excess radio background
• The REACH radiometer for detecting the 21-cm hydrogen signal from redshift 7.5 to 28
• Astrophysical Constraints from the SARAS3 non-detection of the Cosmic Dawn Sky-Averaged 21-cm Signal
• Impact of the Primordial Stellar Initial Mass Function on the 21-cm Signal
• Closing the window on fuzzy dark matter with the 21cm signal
• Antenna beam characterisation for the global 21cm experiment LEDA and its impact on signal model parameter reconstruction
• The Second Radio Synchrotron Background Workshop: Conference Summary and Report
• PRATUSH experiment concept and design overview
• A Bayesian approach to modelling spectrometer data chromaticity corrected using beam factors -- I. Mathematical formalism
• Exploiting synergies between JWST and cosmic 21-cm observations to uncover star formation in the early Universe
• Signatures of Cosmic Ray Heating in 21-cm Observables
• The role of Pop III stars and early black holes in the 21cm signal from Cosmic Dawn
• 21cmFirstCLASS I. Cosmological tool for $\Lambda$CDM and beyond
• A General Bayesian Framework to Account for Foreground Map Errors in Global 21-cm Experiments
• Exploring the cosmic dawn and epoch of reionization with 21cm line
• Accurate modelling of the Lyman-$\alpha$ coupling for the 21-cm signal, observability with NenuFAR and SKA
• Constraining exotic dark matter models with the dark ages 21-cm signal
• Bayesian Data Analysis for Sky-averaged 21-cm Experiments in the Presence of Ionospheric Effects
• Implications of the $z>5$ Lyman-$\alpha$ forest for the 21-cm power spectrum from the epoch of reionization
• Transient RFI environment of LOFAR-LBA at 72-75 MHz: Impact on ultra-widefield AARTFAAC Cosmic Explorer observations of the redshifted 21-cm signal
• Simulation-Based Inference of the sky-averaged 21-cm signal from CD-EoR with REACH
• 21cmFirstCLASS II. Early linear fluctuations of the 21cm signal
• Mapping discrete galaxies at cosmic dawn with 21-centimeter observations
• Cosmic mysteries and the hydrogen 21-cm line: bridging the gap with lunar observations
• Black holes at cosmic dawn in the redshifted 21cm signal of HI
• Radiative transfer of Lyman-$\alpha$ photons at cosmic dawn with realistic gas physics
• Impact of cosmic rays on the global 21-cm signal during cosmic dawn
• The mass distribution of the first stars can be determined via the 21-cm signal
• Rapid and Late Cosmic Reionization Driven by Massive Galaxies: a Joint Analysis of Constraints from 21-cm, Lyman Line & CMB Data Sets
• Large HI optical depth and Redshifted 21-cm signal from cosmic dawn
• Effects of chemically homogeneous evolution of the first stars on the 21-cm signal and reionization
• Understanding spectral artefacts in SKA-LOW 21-cm cosmology experiments: the impact of cable reflections
• STARFIRE: An algorithm for estimating radio frequency interference in orbits around Earth
• Comparison of Bayesian inference methods using the Loreli II database of hydro-radiative simulations of the 21-cm signal
• Global signal in the redshifted hydrogen 21-cm line from the Dark Ages and Cosmic Dawn: Dependence on the nature of dark matter and modeling of first light
• A Bayesian Method to Mitigate the Effects of Unmodelled Time-Varying Systematics for 21-cm Cosmology Experiments
• Detecting Cosmic 21 cm Global Signal Using an Improved Polynomial Fitting Algorithm
• Forecast measurement of the 21 cm global spectrum from Lunar orbit with the Vari-Zeroth-Order Polynomial (VZOP) method
• Narrowing the discovery space of the cosmological 21-cm signal using multi-wavelength constraints
• Ultraviolet photon production rates of the first stars: Impact on the He II $\lambda$ 1640 Å emission line from primordial star clusters and the 21-cm signal from cosmic dawn
• ECHO21: a tool for modelling global 21-cm signal from dark ages to reionization
• 21 cm Signal from the Thermal Evolution of Lyman-$\alpha$ during Cosmic Dawn
• Influence of the deviation of the matter power spectrum at small scales on the global 21-cm signal at cosmic dawn
• The magnitude of the dark ages 21-cm signal in the context of existing early and late time constraints on $\Lambda$CDM
• A Comprehensive Bayesian re-analysis of the SARAS2 data from the Epoch of Reionization
• Exploring delaying and heating effects on the 21-cm signature of fuzzy dark matter
• Classification of Radio Backgrounds at Cosmic Dawn and 21 cm Signal Confirmation Using Neural Networks
• Calibrating Bayesian Tension Statistics using Neural Ratio Estimation
• Optimizing Foreground Modelling for Global 21cm Cosmology with GPU-Accelerated Nested Sampling
• Effect of the cosmological transition to metal-enriched star-formation on the hydrogen 21-cm signal
• The heating rate of the Intergalactic Medium by Lyman-$\alpha$ photon scattering