Bibcode
Chluba, J.; Rubiño-Martín, J. A.; Sunyaev, R. A.
Bibliographical reference
Monthly Notices of the Royal Astronomical Society, Volume 374, Issue 4, pp. 1310-1320.
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2
2007
Citations
78
Refereed citations
75
Description
We present results for the spectral distortions of the cosmic microwave
background (CMB) arising due to bound-bound transitions during the epoch
of cosmological hydrogen recombination at frequencies down to ν
~100MHz. We extend our previous treatment of the recombination problem
now including the main collisional processes and following the evolution
of all the hydrogen angular momentum substates for up to 100 shells. We
show that, due to the low baryon density of the Universe, even within
the highest considered shell full statistical equilibrium (SE) is not
reached and that at low frequencies the recombination spectrum is
significantly different when assuming full SE for n > 2. We also
directly compare our results for the ionization history to the output of
the RECFAST code, showing that especially at low redshifts rather big
differences arise. In the vicinity of the Thomson visibility function
the electron fraction differs by roughly -0.6 per cent which affects the
temperature and polarization power spectra by <~ 1 per cent.
Furthermore, we shortly discuss the influence of free-free absorption
and line broadening due to electron scattering on the bound-bound
recombination spectrum and the generation of CMB angular fluctuations
due to scattering of photons within the high shells.