Chemistry of heavy elements in the Dark Ages

Vonlanthen, Patrick; Rauscher, T.; Winteler, Christian; Puy, D.; Signore, M.; Дубрович, В. К.

doi:10.1051/0004-6361/200811297

Cited by 26 publications

(38 citation statements)

References 78 publications

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“…× 10 −15 . These results are consistent with those of Iocco et al [33] but slightly lower than those of Vonlanthen et al [62]. Detailed CNO, B and Be isotopic abundances, compared with those from Iocco et al [33] can be found in Table 7, together with H, He and Li isotopic abundances compared with our previous work.…”

Section: Resultssupporting

confidence: 92%

Primordial Nucleosynthesis

Coc¹

2013

Acta Phys. Pol. B

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Abstract. Primordial nucleosynthesis, or Big Bang Nucleosynthesis (BBN), is one of the three evidences for the Big-Bang model, together with the expansion of the Universe and the Cosmic Microwave Background. There is a good global agreement over a range of nine orders of magnitude between abundances of 4 He, D, 3 He and 7 Li deduced from observations, and calculated in primordial nucleosynthesis. This comparison was used to determine the baryonic density of the Universe. For this purpose, it is now superseded by the analysis of the Cosmic Microwave Background (CMB) radiation anisotropies. However, there remain, a yet unexplained, discrepancy of a factor 3-5, between the calculated and observed lithium primordial abundances, that has not been reduced, neither by recent nuclear physics experiments, nor by new observations. We review here the nuclear physics aspects of BBN for the production of 4 He, D, 3 He and 7 Li, but also 6 Li, 9 Be, 11 B and up to CNO isotopes. These are, for instance, important for the initial composition of the matter at the origin of the first stars. Big-Bang nucleosynthesis, that has been used, to first constrain the baryonic density, and the number of neutrino families, remains, a valuable tool to probe the physics of the early Universe, like variation of "constants" or alternative theories of gravity.

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Section: Resultssupporting

confidence: 92%

Primordial Nucleosynthesis

Coc¹

2013

Acta Phys. Pol. B

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“…× 10 −15 . These results are consistent with those of Iocco et al [1] but slightly lower than those of Vonlanthen et al [17]. Detailed CNO, B and Be isotopic abundances, compared with those from Iocco et al [1] can be found in Table 2, together with H, He and Li isotopic abundances compared with previous works.…”

Section: Resultssupporting

confidence: 91%

Nuclear uncertainties in CNO production by Big Bang nucleosynthesis

Coc¹,

Goriely²,

Saimpert³

et al. 2012

AIP Conference Proceedings

124

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Abstract. Primordial or Big Bang nucleosynthesis (BBN) is one of the three strong evidences for the Big-Bang model together with the expansion of the Universe and the Cosmic Microwave Background radiation. In this study, we extend the nuclear network until sodium, to evaluate the primordial CNO abundance that could affect Population III stellar evolution. The complete network includes more than 400 reactions, out of which ≈270 reaction rates were calculated using the TALYS code. We performed a sensitivity study to identify the important reactions for CNO nucleosynthesis. We note the stability of results on Big Bang nucleosynthesis CNO production compared to previous works: CNO/H = (0.5 − 3.) × 10 −15 .

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“…Moreover, non-standard BBN models predict heavy nuclei such as carbon, oxygen, nitrogen, and flourine, which may have created molecules like CH, OH, NH, HF, and their respective molecular ions Campos et al 2007;Vonlanthen & Puy 2008;Vonlanthen et al 2009). For example the abundance of the CH molecule is found to be higher than the H 2 D or HD abundances in the inhomogeneous non-standard BBN models.…”

Section: Interesting Speciesmentioning

confidence: 99%

The first spectral line surveys searching for signals from the dark ages

Persson¹,

Maoli

Encrenaz

et al. 2010

A&A

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Aims. Our aim is to observationally investigate the cosmic Dark Ages in order to constrain star and structure formation models, as well as the chemical evolution in the early Universe. Methods. Spectral lines from atoms and molecules in primordial perturbations at high redshifts can give information about the conditions in the early universe before and during the formation of the first stars in addition to the epoch of reionisation. The lines may arise from moving primordial perturbations before the formation of the first stars (resonant scattering lines), or could be thermal absorption or emission lines at lower redshifts. The difficulties in these searches are that the source redshift and evolutionary state, as well as molecular species and transition are unknown, which implies that an observed line can fall within a wide range of frequencies. The lines are also expected to be very weak. Observations from space have the advantages of stability and the lack of atmospheric features which is important in such observations. We have therefore, as a first step in our searches, used the Odin satellite to perform two sets of spectral line surveys towards several positions. The first survey covered the band 547−578 GHz towards two positions, and the second one covered the bands 542.0−547.5 GHz and 486.5−492.0 GHz towards six positions selected to test different sizes of the primordial clouds. Two deep searches centred at 543.250 and 543.100 GHz with 1 GHz bandwidth were also performed towards one position. The two lowest rotational transitions of H 2 will be redshifted to these frequencies from z ∼ 20−30, which is the predicted epoch of the first star formation. Results. No lines are detected at an rms level of 14−90 and 5−35 mK for the two surveys, respectively, and 2−7 mK in the deep searches with a channel spacing of 1−16 MHz. The broad bandwidth covered allows a wide range of redshifts to be explored for a number of atomic and molecular species and transitions. From the theoretical side, our sensitivity analysis show that the largest possible amplitudes of the resonant lines are about 1 mK at frequencies < ∼ 200 GHz, and a few μK around 500−600 GHz, assuming optically thick lines and no beam-dilution. However, if existing, thermal absorption lines have the potential to be orders of magnitude stronger than the resonant lines. We make a simple estimation of the sizes and masses of the primordial perturbations at their turnaround epochs, which previously has been identified as the most favourable epoch for a detection. This work may be considered as an important pilot study for our forthcoming observations with the Herschel Space Observatory.

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Chemistry of heavy elements in the Dark Ages

Cited by 26 publications

References 78 publications

Primordial Nucleosynthesis

Primordial Nucleosynthesis

Nuclear uncertainties in CNO production by Big Bang nucleosynthesis

The first spectral line surveys searching for signals from the dark ages

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