EDP Sciences
Free Access
Volume 475, Number 1, November III 2007
Page(s) 109 - 114
Section Cosmology (including clusters of galaxies)
DOI https://doi.org/10.1051/0004-6361:20077333
Published online 02 October 2007

A&A 475, 109-114 (2007)
DOI: 10.1051/0004-6361:20077333

Cosmological hydrogen recombination: Lyn line feedback and continuum escape

J. Chluba1 and R. A. Sunyaev1, 2

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 )

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-(n-1) transitions yields a maximal correction of $\Delta N_{\rm e}/N_{\rm e}\sim 0.22\%$ at $z\sim
1050$. Including only Lyman-$\beta$ feedback onto the Lyman-$\alpha$ 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 $\vert\Delta
C^{TT}_l/C^{TT}_l\vert\sim 0.15\%$ and $\vert\Delta C^{EE}_l/C^{EE}_l\vert\sim 0.36\%$ at $l\lesssim 3000$. The escape in the Lyman-continuum and feedback of Lyman-$\alpha$ photons on the photoionization rate of the second shell lead to modifications of the ionization history which are very small (less than $\vert\Delta N_{\rm
e}/N_{\rm e}\vert\sim {\rm few}\times 10^{-6}$).

Key words: cosmic microwave background -- cosmology: miscellaneous

© ESO 2007

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