Cosmological hydrogen recombination: influence of resonance and electron scattering
Bibliographic record
Abstract
In this paper we consider the effects of resonance and electron scattering on the escape of Lyman α photons during cosmological hydrogen recombination. We pay particular attention to the influence of atomic recoil, Doppler boosting, and Doppler broadening using a Fokker-Planck approximation of the redistribution function describing the scattering of photons on the Lyman α resonance of moving hydrogen atoms. We extend the computations of our recent paper on the influence of the 3d/3s-1s two-photon channels on the dynamics of hydrogen recombination, simultaneously including the full time dependence of the problem, the thermodynamic corrections factor, leading to a frequency-dependent asymmetry between the emission and absorption profile, and the quantum-mechanical corrections related to the two-photon nature of the 3d/3s-1s emission and absorption process on the exact shape of the Lyman α emission profile. We show here that, because of the redistribution of photons over frequency hydrogen recombination is sped up by ~ -0.6% at z ~ 900. For the CMB temperature and polarization power spectra, this results in ~ 0.5-1% at ly 1500, which is in turn important for analyzing future CMB data in the context of the Planck Surveyor, Spt, and Act. The main contribution to this correction comes from the atomic recoil effect ( ~ -1.2% at z ~ 900), while Doppler boosting and Doppler broadening partially cancel this correction, again slowing hydrogen recombination down by ~ 0.6% at z ~ 900. The influence of electron scattering close to the maximum of the Thomson visibility function at z ~ 1100 can be neglected. We also give the cumulative results, in addition including the time-dependent correction, the thermodynamic factor, and the correct shape of the emission profile. This amounts to ~ -1.8% at z ~ 1160 and ~ 1-3% at l 1500.
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How this classification was reachedexpand
Full frame machine prediction
Teacher imitationNot calibrated prevalence, not ground truth. Human validation pending. The Gemma side is a direct model label for every work in the frame, read from the title-only record. The Codex side is a classifier learned from the 10,348 direct Codex labels and calibrated to design-weighted sample rates; fields without enough sample support carry no Codex call. Candidate is the union of the two sides; consensus is their intersection. These outputs are machine_predicted_unvalidated and are not human labels.
Distilled classifier scores by category (both heads)
| Category | Codex | Gemma |
|---|---|---|
| Metaresearch | 0.000 | 0.002 |
| Meta-epidemiology (narrow) | 0.000 | 0.000 |
| Meta-epidemiology (broad) | 0.000 | 0.001 |
| Bibliometrics | 0.000 | 0.000 |
| Science and technology studies | 0.000 | 0.001 |
| Scholarly communication | 0.001 | 0.001 |
| Open science | 0.001 | 0.001 |
| Research integrity | 0.000 | 0.001 |
| Insufficient payload (model declined to judge) | 0.002 | 0.000 |
Machine scores (provisional)
The two teacher heads of the student model, read on this work. A score orders the frame for review; it never asserts a category, and the validation status ships verbatim with every row.
Baseline scores from an immature model (maturity gate not passed, 7 training rounds). Scores rank; they never assert a category.
score_only:v0-immature-baseline · verbatim from the scoring run: score_only means the number may rank works, and no category label ships from itClassification
machine, unvalidatedMachine predicted; a candidate call from one source (direct Gemma or distilled Codex), not a consensus.
How this classification was reached, model by model and score by score, is at the end of the page under "How this classification was reached".