Recombination dynamics of primordial hydrogen and helium (He I) in the universe
- 56 Downloads
We calculated the ionization fraction for hydrogen and helium (He I) as a function of the redshift z by including the two-photon decays of high hydrogen and parahelium levels and the radiative transfer in the helium 23P1 ↔ 11S0 intercombination line. We show that this yields corrections of no more than a few percent to the ionization fraction for hydrogen and speeds up significantly the recombination for helium compared to the recent works by Seager et al. (1999, 2000), in which these effects were disregarded.
Key wordscosmology early Universe primordial helium recombination radio astronomy cosmic microwave background radiation
Unable to display preview. Download preview PDF.
- 1.I. L. Beigman and M. I. Syrkin, Preprint No. 295, FIAN (Lebedev Phys. Inst. USSR Acad. Sci., Moscow, 1983).Google Scholar
- 2.V. B. Berestetskii, E. M. Lifshits, and L. P. Pitaevskii, Quantum Electrodynamics (Nauka, Moscow, 1989; Pergamon Press, Oxford, 1982).Google Scholar
- 3.V. K. Dubrovich, Opt. Spektrosk. 63, 439 (1987) [Opt. Spectrosc. 63, 256 (1987)].Google Scholar
- 4.S. I. Grachev, Tr. Astron. Obs. Sankt-Peterburg. Gos. Univ. 44, 203 (1994).Google Scholar
- 7.A. Ya. Kipper, in On the Development of Soviet Science in ESSR 1940–1950 (Tallin, 1950) [in Russian].Google Scholar
- 12.V. V. Sobolev, Moving Stellar Envelopes (Leningr. Gos. Univ., Leningrad, 1947) [in Russian].Google Scholar