Relative Contribution of the Hydrogen 2 s Two-Photon Decay and Lyman- α Escape Channels during the Epoch of Cosmological Recombination
Abstract
We discuss the evolution of the ratio in number of recombinations due to 2 s two photon escape and due to the escape of Lyman- α photons from the resonance during the epoch of cosmological recombination, within the width of the last scattering surface and near its boundaries. We discuss how this ratio evolves in time, and how it defines the profile of the Lyman- α line in the spectrum of CMB. One of the key reasons for explaining its time dependence is the strong overpopulation of the 2 p level relative to the 2 s level at redshifts z ≲ 750.
- Publication:
-
Astronomy Letters
- Pub Date:
- January 2018
- DOI:
- 10.1134/S1063773718010036
- arXiv:
- arXiv:1711.05533
- Bibcode:
- 2018AstL...44....1R
- Keywords:
-
- atomic processes—cosmic microwave background—cosmology;
- theory—early Universe;
- Astrophysics - Cosmology and Nongalactic Astrophysics
- E-Print:
- Accepted for publication in Astronomy Letters