The Time Development of a Resonance Line in the Expanding Universe

Abstract

The time-dependent spectral profile of a resonance line in a homogeneous expanding medium is studied by numerically solving an improved Fokker-Planck diffusion equation. The solutions are used to determine the time required to reach a quasi-static solution near the line center. A simple scaling law for this relaxation time is derived and is fitted to the numerical results. The results are applied to the case of Lyman alpha scattering during primordial recombination of hydrogen. For a wide range of cosmological models it is found that the relaxation times are smaller than the recombination timescale, although not by a very large factor. Thus the standard assumption of a quasi-static solution in cosmological recombination calculations is reasonably valid, and should not cause substantial errors in the solutions.

20 pages text and 10 figures, in 30 pages of uuencoded, compressed postscript. CFA preprint no. 3753

Cited by in corpus (68)

• Cosmology at Low Frequencies: The 21 cm Transition and the High-Redshift Universe
• 21-cm Tomography of the Intergalactic Medium at High Redshift
• How exactly did the Universe become neutral?
• Lyman Alpha Radiation From Collapsing Protogalaxies I: Characteristics of the Emergent Spectrum
• Lyman Alpha Emitting Galaxies as a Probe of Reionization
• Wouthuysen-Field coupling strength and application to high-redshift 21 cm radiation
• HyRec: A fast and highly accurate primordial hydrogen and helium recombination code
• The Spin-Kinetic Temperature Coupling and the Heating Rate due to Lyman Alpha Scattering before Reionization: Predictions for 21cm Emission and Absorption
• The Effect of Physical Assumptions on the Calculation of Microwave Background Anisotropies
• Towards a complete treatment of the cosmological recombination problem
• The Rise of the First Stars: Supersonic Streaming, Radiative Feedback, and 21-cm Cosmology
• Constraining primordial black holes as dark matter using the global 21-cm signal with X-ray heating and excess radio background
• Lines in the Cosmic Microwave Background Spectrum from the Epoch of Cosmological Hydrogen Recombination
• Lines in the cosmic microwave background spectrum from the epoch of cosmological helium recombination
• The Scattering of Lyman-series Photons in the Intergalactic Medium
• Primordial helium recombination I: feedback, line transfer, and continuum opacity
• Heating of the intergalactic medium by the cosmic microwave background during cosmic dawn
• Two-photon transitions in hydrogen and cosmological recombination
• Two-photon transitions in primordial hydrogen recombination
• HI Signal from Reionization Epoch
• UV pumping of hyperfine transitions in the light elements, with application to 21-cm hydrogen and 92-cm deuterium lines from the early universe
• Lyman-$\alpha$ coupling and heating at Cosmic Dawn
• Rico: An Accurate Cosmological Recombination Code
• Lyman Alpha Signatures from Direct Collapse Black Holes
• Primordial helium recombination III: Thomson scattering, isotope shifts, and cumulative results
• Lyman-alpha transfer in primordial hydrogen recombination
• Primordial magnetic fields and the HI signal from the epoch of reionization
• Improved Fokker-Planck Equation for Resonance Line Scattering
• Cosmological Hydrogen Recombination: influence of resonance and electron scattering
• Primordial helium recombination II: two-photon processes
• Time-Dependent Corrections to the Ly-alpha Escape Probability During Cosmological Hydrogen Recombination
• Using the cosmological recombination radiation to probe early dark energy and fundamental constant variations
• Energy transfer by the scattering of resonant photons
• Spectral distortions of the CMB dipole
• Perturbations of ionization fractions at the cosmological recombination epoch
• Radiative transfer effects in primordial hydrogen recombination
• Sensitivity forecasts for the cosmological recombination radiation in the presence of foregrounds
• Quasars as probes of cosmological reionization
• Discrete diffusion Lyman-alpha radiative transfer
• The scattering of LyA radiation in the intergalactic medium: numerical methods and solutions
• Lyman-$\alpha$ feedback prevails at Cosmic Dawn: Implications for the first galaxies, stars, and star clusters
• Accurate modelling of the Lyman-$\alpha$ coupling for the 21-cm signal, observability with NenuFAR and SKA
• Resonant-line radiative transfer within power-law density profiles
• Molecular hydrogen in the cosmic recombination epoch
• An Analytic Formulation of 21-cm Signal from Early Phase of Epoch of Reionization
• Time evolution of Wouthuysen-Field coupling
• A WENO algorithm for radiative transfer with resonant scattering: the time scale of the Wouthuysen-Field Coupling
• New Horizons in Cosmology with Spectral Distortions of the Cosmic Microwave Background
• A closer look at dark photon explanations of the excess radio background
• Wouthuysen-Field Coupling in the 21 cm Region Around High Redshift Sources
• The impact of Lyman-$\alpha$ emission line heating and cooling on the cosmic dawn 21-cm signal
• The Wouthuysen-Field effect in a clumpy intergalactic medium
• The ultimate frontier of 21cm cosmology
• Time-Dependent Behavior of Lyman$\alpha$ Photon Transfer in High Redshift Optically Thick Medium
• Hydrogen 2p--2s transition: signals from the epochs of recombination and reionization
• Importance of intracluster scattering and relativistic corrections from tSZ effect with Cosmic Infrared Background
• Analytic Formulation of 21 cm Signal from Cosmic Dawn: Ly$\alpha$ Fluctuations
• Lyman-alpha Heating of Inhomogeneous High-redshift Intergalactic Medium
• Effect of Dust on Lyman-alpha Photon Transfer in Optically Thick Halo
• Lyman-alpha resonant-line radiative transfer in expanding media
• Energy injection in pre-recombination era and EDGES detection
• Signals of the cosmological reionization in the radio sky through C and O fine structure lines
• Stability of small-scale baryon perturbations during cosmological recombination
• A Novel Solution for Resonant Scattering Using Self-Consistent Boundary Conditions
• 21 cm Signal from the Thermal Evolution of Lyman-$\alpha$ during Cosmic Dawn
• Thermal Evolution of the IGM due to Lyman-α photons during the Cosmic Dawn
• Relative contribution of the hydrogen 2S two-photon decay and Lyman-alpha escape channels during the epoch of cosmological recombination
• The heating rate of the Intergalactic Medium by Lyman-$\alpha$ photon scattering