EDP Sciences
Free Access
Volume 446, Number 1, January IV 2006
Page(s) 39 - 42
Section Cosmology (including clusters of galaxies)
DOI https://doi.org/10.1051/0004-6361:20053988

A&A 446, 39-42 (2006)
DOI: 10.1051/0004-6361:20053988

Induced two-photon decay of the 2s level and the rate of cosmological hydrogen recombination

J. Chluba1 and R. A. Sunyaev1, 2

1  Max-Planck-Institut für Astrophysik, Karl-Schwarzschild-Str. 1, 86740 Garching bei München, Germany
    e-mail: jchluba@mpa-garching.mpg.de
2  Space Research Institute, Russian Academy of Sciences, Profsoyuznaya 84/32 Moscow, Russia

(Received 5 August 2005/ Accepted 2 September 2005)

Induced emission due to the presence of soft CMB photons slightly increases the two-photon decay rate of the 2s level of hydrogen defining the rate of cosmological recombination. This correspondingly changes the degree of ionization, the visibility function and the resulting primordial temperature anisotropies and polarization of the CMB on the percent level. These changes exceed the precision of the widely used CMBFAST and CAMB codes by more than one order of magnitude and can be easily taken into account.

Key words: cosmology: cosmic microwave background -- cosmology: miscellaneous

© ESO 2006