Heavy element production in inhomogeneous big bang nucleosynthesis

Matsuura, Shunji; Fujimoto, Shin-ichiro; Nishimura, S.; Hashimoto, M.; Sato, Katsuhiko

doi:10.1103/physrevd.72.123505

Cited by 33 publications

(41 citation statements)

References 46 publications

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“…This is similar to the scenario originally introduced by Jedamzik et al (1994) and later also discussed by Matsuura et al (2004Matsuura et al ( , 2005Matsuura et al ( , 2007. In the high density pocket the path to heavy elements is opened by an efficient triple-α reaction.…”

mentioning

confidence: 53%

Chemistry of heavy elements in the Dark Ages

Vonlanthen¹,

Rauscher

Winteler

et al. 2009

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Context. Primordial molecules were formed during the Dark Ages, i.e. the time between recombination and reionization in the early Universe. They were the constituents of the first proto-stellar clouds. Standard Big Bang nucleosynthesis predicts the abundances of hydrogen, helium, lithium, beryllium, and their isotopes in the early Universe. Heavier nuclei such as carbon, nitrogen, or oxygen are only formed in trace amounts. In nonstandard Big Bang nucleosynthesis models, it is possible to synthesize greater quantities of these heavier elements. The latter are interesting because they can form molecules with a high electric dipole moment which can increase the cooling in collapsing protostellar structures. Aims. The purpose of this article is to analyze the formation of primordial molecules based on heavy elements during the Dark Ages, with elemental abundances taken from different nucleosynthesis models. Methods. We present calculations of the full nonlinear equation set governing the primordial chemistry. We considered the evolution of 45 chemical species and used an implicit multistep method of variable order of precision with an adaptive stepsize control. Results. The cosmological recombination of heavy elements is presented for the first time. We find that the most abundant Dark Age molecules based on heavy elements are CH and OH. When considering initial conditions given by the standard Big Bang nucleosynthesis model, we obtain relative abundances [CH] = n CH /n b = 6.2 × 10 −21 and [OH] = n OH /n b = 1.2 × 10 −23 at z = 10, where n b is the total number density. But nonstandard nucleosynthesis can lead to higher heavy element abundances, while still satisfying the observed primordial light abundances. In that case, we show that the abundances of molecular species based on C, N, O, and F can be enhanced by two orders of magnitude, leading to a CH relative abundance higher than that of HD + or H 2 D + .

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confidence: 53%

Chemistry of heavy elements in the Dark Ages

Vonlanthen¹,

Rauscher

Winteler

et al. 2009

A&A

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“…In the standard BBN scenario, elements heavier than lithium are only produced with trace abundances [3]. It has been shown, however, that significant amounts of heavy elements may be produced in inhomogeneous BBN (IBBN) models [4][5][6]. IBBN may take place if some nonstandard mechanism leads to large baryon-abundance inhomogeneities on small scales, which are allowed by current observations.…”

Section: Introductionmentioning

confidence: 88%

Metals at the surface of last scatter

2011

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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 photons can be removed (and recombination thus accelerated) by photoionizing metals; (2) The Bowen resonance-fluorescence mechanism may degrade Ly photons and thus enhance the Ly 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-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.

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“…We studied heavy element production in the high baryon density region in the early universe [3]. However it is claimed by [1] that a small scale but high baryon density region contradicts observations for the light element abundance or, in order not to contradict to the observations the high density region must be so small that it cannot affect the present heavy element abundance.…”

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confidence: 92%

“…In the previous paper [3], we studied heavy element production in inhomogeneous BBN from this point of view.…”

Section: Introductionmentioning

confidence: 99%

Reply to “Comment on ‘Heavy element production in inhomogeneous big bang nucleosynthesis’”

et al. 2007

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This is a reply report to [1]. We studied heavy element production in the high baryon density region in the early universe [3]. However it is claimed by [1] that a small scale but high baryon density region contradicts observations for the light element abundance or, in order not to contradict to the observations the high density region must be so small that it cannot affect the present heavy element abundance.In this paper we study big bang nucleosynthesis in the high baryon density region and show that in certain parameter spaces it is possible to produce enough amount of the heavy element without contradiction to cosmic microwave background and light element observations.

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Heavy element production in inhomogeneous big bang nucleosynthesis

Cited by 33 publications

References 46 publications

Chemistry of heavy elements in the Dark Ages

Chemistry of heavy elements in the Dark Ages

Metals at the surface of last scatter

Reply to “Comment on ‘Heavy element production in inhomogeneous big bang nucleosynthesis’”

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