Lines in the cosmic microwave background spectrum from the epoch of cosmological helium recombination

Abstract

The main goal of this work is to calculate the contributions to the cosmological recombination spectrum due to bound-bound transitions of helium. We show that due to the presence of helium in the early Universe unique features appear in the total cosmological recombination spectrum. These may provide a unique observational possibility to determine the relative abundance of primordial helium, well before the formation of first stars. We include the effect of the tiny fraction of neutral hydrogen atoms on the dynamics of HeII -> HeI recombination at redshifts $z\sim 2500$. As discussed recently, this process significantly accelerates HeII -> HeI recombination, resulting in rather narrow and distinct features in the associated recombination spectrum. In addition this process induces some emission within the hydrogen Lyman-$\alpha$ line, before the actual epoch of hydrogen recombination round $z\sim 1100-1500$. We also show that some of the fine structure transitions of neutral helium appear in absorption, again leaving unique traces in the Cosmic Microwave Background blackbody spectrum, which may allow to confirm our understanding of the early Universe and detailed atomic physics.

arXiv comment17 pages, 16 figures. Accepted for publication in A&A. Our final computations can be downloaded from http://www.iac.es/galeria/jalberto/recomb

References in corpus (17)

• First Year Wilkinson Microwave Anisotropy Probe (WMAP) Observations: Preliminary Maps and Basic Results
• How exactly did the Universe become neutral?
• Primordial Nucleosynthesis for the New Cosmology: Determining Uncertainties and Examining Concordance
• Improving Predictions for Helium Emission Lines
• The Effect of Physical Assumptions on the Calculation of Microwave Background Anisotropies
• On the Abundance of Primordial Helium
• Induced two-photon decay of the 2s level and the rate of cosmological hydrogen recombination
• Lines in the Cosmic Microwave Background Spectrum from the Epoch of Cosmological Hydrogen Recombination
• Cosmological hydrogen recombination: populations of the high level sub-states
• The Time Development of a Resonance Line in the Expanding Universe
• Free-bound emission from cosmological hydrogen recombination
• The effect of forbidden transitions on cosmological hydrogen and helium recombination
• Two-Photon 2s<->1s Transitions during Recombination of Hydrogen in the Universe
• Rapid HeII->HeI recombination and radiation concerned with this process
• Forbidden transitions in the helium atom
• J-resolved He I emission predictions in the low-density limit
• Spectral distortions to the Cosmic Microwave Background from the recombination of hydrogen and helium

Cited by in corpus (67)

• Planck 2015 results. XIII. Cosmological parameters
• The evolution of CMB spectral distortions in the early Universe
• HyRec: A fast and highly accurate primordial hydrogen and helium recombination code
• PRISM (Polarized Radiation Imaging and Spectroscopy Mission): An Extended White Paper
• Exploring Cosmic Origins with CORE: Cosmological Parameters
• Towards a complete treatment of the cosmological recombination problem
• Which spectral distortions does $\Lambda$CDM actually predict?
• Ultrafast effective multi-level atom method for primordial hydrogen recombination
• Could the Cosmological Recombination Spectrum Help Us Understand Annihilating Dark Matter?
• Distinguishing different scenarios of early energy release with spectral distortions of the cosmic microwave background
• New constraints on time-dependent variations of fundamental constants using Planck data
• CMB and BBN constraints on evaporating primordial black holes revisited
• Signals From the Epoch of Cosmological Recombination
• Recombinations to the Rydberg States of Hydrogen and Their Effect During the Cosmological Recombination Epoch
• The synergy between CMB spectral distortions and anisotropies
• Green's function of the cosmological thermalization problem II: effect of photon injection and constraints
• Spectral distortion constraints on photon injection from low-mass decaying particles
• Mixing of blackbodies: entropy production and dissipation of sound waves in the early Universe
• Creation of the CMB spectrum: precise analytic solutions for the blackbody photosphere
• Estimating the impact of recombination uncertainties on the cosmological parameter constraints from cosmic microwave background experiments
• Unavoidable CMB spectral features and blackbody photosphere of our Universe
• Does Bose-Einstein condensation of CMB photons cancel μ distortions created by dissipation of sound waves in the early Universe?
• Forecasts for CMB μ- and i-type spectral distortion constraints on the primordial power spectrum on scales 8 < k < 10^4 Mpc^-1 with the future Pixie-like experiments
• On the detection of spectral ripples from the Recombination Epoch
• CosmoSpec: Fast and detailed computation of the cosmological recombination radiation from hydrogen and helium
• HYREC-2: a highly accurate sub-millisecond recombination code
• Rico: An Accurate Cosmological Recombination Code
• Tests of the CMB temperature-redshift relation, CMB spectral distortions and why adiabatic photon production is hard
• Pre-recombinational energy release and narrow features in the CMB spectrum
• Lyman-alpha transfer in primordial hydrogen recombination
• Precise cosmological parameter estimation using CosmoRec
• CMB anisotropy and BBN constraints on pre-recombination decay of dark matter to visible particles
• Microwave Spectro-Polarimetry of Matter and Radiation across Space and Time
• Testing dark matter interactions with CMB spectral distortions
• Cosmological Hydrogen Recombination: influence of resonance and electron scattering
• Cosmological recombination: feedback of helium photons and its effect on the recombination spectrum
• Non-thermal photons and H2 formation in the early Universe
• Uncertainties in Theoretical HeI Emissivities: HII Regions, Primordial Abundance, and Cosmological Recombination
• 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
• Non-equilibrium H${}_2$ formation in the early Universe: energy exchanges, rate coefficients and spectral distortions
• Radiative transfer effects during primordial helium recombination
• Spectral distortions of the CMB dipole
• Effective conductance method for the primordial recombination spectrum
• Radiative transfer effects in primordial hydrogen recombination
• Sensitivity forecasts for the cosmological recombination radiation in the presence of foregrounds
• Ly alpha escape during cosmological hydrogen recombination: the 3d-1s and 3s-1s two-photon processes
• Spectral Distortion of the CMB by the Cumulative CO Emission from Galaxies throughout Cosmic History
• Constraints on Gravitino Decay and the Scale of Inflation using CMB spectral distortions
• Evolution of low-frequency features in the CMB spectrum due to stimulated Compton scattering and Doppler-broadening
• Probing early-universe phase transitions with CMB spectral distortions
• Molecular hydrogen in the cosmic recombination epoch
• Effect of Radiative Feedbacks for Resonant Transitions during Cosmological Recombination
• The first spectral line surveys searching for signals from the Dark Ages
• The clustering of galaxies in the SDSS-III Baryon Oscillation Spectroscopic Survey: constraints on the time variation of fundamental constants from the large-scale two-point correlation function
• New Horizons in Cosmology with Spectral Distortions of the Cosmic Microwave Background
• Reassessing Dust's Role in Forming the CMB
• Advanced Three Level Approximation for Numerical Treatment of Cosmological Recombination
• Hydrogen Recombination with Multilevel atoms
• Cosmology with Recombination Spectrum
• The Thermal Sunyaev-Zeldovich Effect of Primordial Recombination Radiation
• A Pop III generated dust screen at z~16
• Non-thermal photons and direct photodissociation of H2, HD and HeH+ in the chemistry of the primordial Universe
• Investigation of the electromagnetically induced transparency in era of cosmological hydrogen recombination
• The Anomalous 21-cm Absorption at High Redshifts
• Vertex-type thermal correction to the one-photon transition rates
• Spectral Variations of the Sky: Constraints on Alternate Universes