Metals at the surface of last scatter

Journal Article · Fri Apr 15 00:00:00 EDT 2011 · Physical Review. D, Particles Fields

DOI:https://doi.org/10.1103/PHYSREVD.83.083508· OSTI ID:21541449

Ali-Haiemoud, Yacine; Hirata, Christopher M; Kamionkowski, Marc ^[1]

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1. California Institute of Technology, Mail Code 350-17, Pasadena, California 91125 (United States)

Standard big-bang nucleosynthesis (BBN) predicts only a trace abundance of lithium and no heavier elements, but some alternatives predict a nonzero primordial metallicity. Here we explore whether CMB measurements may set useful constraints to the primordial metallicity and/or whether the standard CMB calculations are robust, within the tolerance of forthcoming CMB maps, to the possibility of primordial metals. Metals would affect the recombination history (and thus CMB power spectra) in three ways: (1) Ly{alpha} photons can be removed (and recombination thus accelerated) by photoionizing metals; (2) The Bowen resonance-fluorescence mechanism may degrade Ly{beta} photons and thus enhance the Ly{beta} escape probability and speed up recombination; (3) Metals could affect the low-redshift tail of the CMB visibility function by providing additional free electrons. The last two of these provide the strongest CMB signal. However, the effects are detectable in the Planck satellite only if the primordial metal abundance is at least a few hundredths of solar for (2) and a few tenths of solar for (3). We thus conclude that Planck will not be able to improve upon current constraints to primordial metallicity, at the level of a thousandth of solar, from the Lyman-{alpha} forest and ultra-metal-poor halo stars, and that the CMB power-spectrum predictions for Planck suffer no uncertainty arising from the possibility that there may be primordial metals.

• OSTI ID: 21541449
• Journal Information: Physical Review. D, Particles Fields, Vol. 83, Issue 8; Other Information: DOI: 10.1103/PhysRevD.83.083508; (c) 2011 American Institute of Physics; ISSN 0556-2821
• Country of Publication: United States
• Language: English

Related Subjects

72 PHYSICS OF ELEMENTARY PARTICLES AND FIELDS
ELECTRONS
FORECASTING
LITHIUM
NUCLEOSYNTHESIS
PHOTOIONIZATION
PHOTONS
PROBABILITY
RECOMBINATION
RED SHIFT
RELICT RADIATION
RESONANCE FLUORESCENCE
SPECTRA
SURFACES
TOLERANCE
VELOCITY
ALKALI METALS
BOSONS
ELECTROMAGNETIC RADIATION
ELEMENTARY PARTICLES
ELEMENTS
EMISSION
FERMIONS
FLUORESCENCE
IONIZATION
LEPTONS
LUMINESCENCE
MASSLESS PARTICLES
METALS
MICROWAVE RADIATION
PHOTON EMISSION
RADIATIONS
SYNTHESIS