Cosmological hydrogen recombination: Lyn line feedback and continuum escape

¹ Max-Planck-Institut für Astrophysik, Karl-Schwarzschild-Str. 1, 85741 Garching bei München, Germany e-mail: jchluba@mpa-garching.mpg.de
² Space Research Institute, Russian Academy of Sciences, Profsoyuznaya 84/32, 117997 Moscow, Russia

Received: 20 February 2007
Accepted: 16 September 2007

Abstract

We compute the corrections to the cosmological hydrogen recombination history due to delayed feedback of Lyman-series photons and the escape in the Lyman-continuum. The former process is expected to slightly delay recombination, while the latter should allow the medium to recombine a bit faster. It is shown that the subsequent feedback of released Lyman-n photons on the lower lying Lyman- transitions yields a maximal correction of at . Including only Lyman-β feedback onto the Lyman-α transition, accounts for most of the effect. We find corrections to the cosmic microwave background TT and EE power spectra with typical peak to peak amplitude and at . The escape in the Lyman-continuum and feedback of Lyman-α photons on the photoionization rate of the second shell lead to modifications of the ionization history which are very small (less than ).