Free-bound emission from cosmological hydrogen recombination

2006/08/04 by J. Chluba, R. A. Sunyaev · 10 citations
Physics and Astronomy · #Atom (system on chip) #Cosmology and Gravitation Theories #Electron #Galaxies: Formation, Evolution, Phenomena #Hydrogen #Hydrogen atom #Photon #Radio Astronomy Observations and Technology #Range (aeronautics) #Recombination #Spontaneous emission #astro-ph

paper · pdf · doi:10.1051/0004-6361:20066191

4 pages, 2 figures, submitted to A&A Letters

arxiv created 2006/08/04 · openalex publication_date 2006/09/15 · arxiv updated 2009/12/01 · openalex created_date 2016/06/24 · openalex updated_date 2026/08/05

Abstract

In this letter we compute the emission coming from the direct recombination of free electrons to a given shell () during the epoch of cosmological hydrogen recombination. This contribution leads to a total of one photon per recombined hydrogen atom and therefore a ~ increase in the recombination spectrum within the frequency range . In particular, the Balmer-continuum emission increases the distortion at GHz by roughly . With our 100 shell calculations for the hydrogen atom, we find that a total of ~5 photons per hydrogen atom are emitted when including all the bound-bound transitions, the 2s two-photon decay channel, and the optically thin free-bound transitions. Since the direct recombination continuum at high n is very broad, only a few n-series continuua are distinguishable and most of this additional emission below GHz is completely featureless.

Citations

• Recombination induced softening and reheating of the cosmic plasma

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