Astronomy Letters

, Volume 31, Issue 6, pp 359–364 | Cite as

Recombination dynamics of primordial hydrogen and helium (He I) in the universe

  • V. K. Dubrovich
  • S. I. Grachev


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 words

cosmology early Universe primordial helium recombination radio astronomy cosmic microwave background radiation 


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  1. 1.
    I. L. Beigman and M. I. Syrkin, Preprint No. 295, FIAN (Lebedev Phys. Inst. USSR Acad. Sci., Moscow, 1983).Google Scholar
  2. 2.
    V. B. Berestetskii, E. M. Lifshits, and L. P. Pitaevskii, Quantum Electrodynamics (Nauka, Moscow, 1989; Pergamon Press, Oxford, 1982).Google Scholar
  3. 3.
    V. K. Dubrovich, Opt. Spektrosk. 63, 439 (1987) [Opt. Spectrosc. 63, 256 (1987)].Google Scholar
  4. 4.
    S. I. Grachev, Tr. Astron. Obs. Sankt-Peterburg. Gos. Univ. 44, 203 (1994).Google Scholar
  5. 5.
    S. I. Grachev and V. K. Dubrovich, Astrofizika 34, 249 (1991) [Astrophys. 34, 124 (1991)].ADSGoogle Scholar
  6. 6.
    W. Hu, D. Scott, N. Sugiyama, and M. White, Phys. Rev. D 52, 5498 (1995).ADSGoogle Scholar
  7. 7.
    A. Ya. Kipper, in On the Development of Soviet Science in ESSR 1940–1950 (Tallin, 1950) [in Russian].Google Scholar
  8. 8.
    C. D. Lin, W. R. Johnson, and A. Dalgarno, Phys. Rev. A 15, 154 (1977).ADSGoogle Scholar
  9. 9.
    P. J. E. Peebles, Astrophys. J. 153, 1 (1968).ADSGoogle Scholar
  10. 10.
    S. Seager, D. D. Sasselov, and D. Scott, Astrophys. J. 523, L1 (1999).CrossRefADSGoogle Scholar
  11. 11.
    S. Seager, D. D. Sasselov, and D. Scott, Astrophys. J., Suppl. Ser. 128, 407 (2000).CrossRefADSGoogle Scholar
  12. 12.
    V. V. Sobolev, Moving Stellar Envelopes (Leningr. Gos. Univ., Leningrad, 1947) [in Russian].Google Scholar
  13. 13.
    Ya. B. Zel’dovich, V. G. Kurt, and R. A. Sunyaev, Zh. Éksp. Teor. Fiz. 55, 278 (1968) [Sov. Phys. JETP 28, 146 (1968)].ADSGoogle Scholar

Copyright information

© Pleiades Publishing, Inc. 2005

Authors and Affiliations

  • V. K. Dubrovich
    • 1
    • 2
  • S. I. Grachev
    • 3
  1. 1.Special Astrophysical Observatory, St. Petersburg BranchRussian Academy of SciencesSt. PetersburgRussia
  2. 2.Pulkovo Astronomical ObservatoryRussian Academy of SciencesSt. PetersburgRussia
  3. 3.Sobolev Astronomical InstituteSt. Petersburg State UniversitySt. PetersburgRussia

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