Influence of gamma-ray emission on the isotopic composition of clouds in the interstellar medium

Клименко, В. В.; Ivanchik, A. V.; Pavlov, Artyom

doi:10.1134/s1063773712060035

Cited by 2 publications

(2 citation statements)

References 53 publications

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“…It is possible that the dispersion is real. However, no reason for this is known for the moment (see., e. g., Klimenko et al 2012). As metallicity is low in these systems (see Table 3), an astration correction for D is assumed to be negligible.…”

Section: Sources Of Uncertaintiesmentioning

confidence: 99%

The primordial deuterium abundance: subDLA system atz_abs = 2.437 towards the QSO J 1444+2919

Balashev¹,

Zavarygin²,

Ivanchik³

et al. 2016

Mon. Not. R. Astron. Soc.

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We report a new detection of neutral deuterium in the sub Damped Lyman Alpha system with low metallicity [O/H] = −2.042 ± 0.005 at z abs = 2.437 towards QSO J 1444+2919. The hydrogen column density in this system is logN (H i) = 19.983 ± 0.010 and the measured value of deuterium abundance is log(D/H) = −4.706 ± 0.007 stat ± 0.067 syst . This system meets the set of strict selection criteria stated recently by Cooke et al. and, therefore, widens the Precision Sample of D/H. However, possible underestimation of systematic errors can bring bias into the mean D/H value (especially if use a weighted mean). Hence, it might be reasonable to relax these selection criteria and, thus, increase the number of acceptable absorption systems with measured D/H values. In addition, an unweighted mean value might be more appropriate to describe the primordial deuterium abundance. The unweighted mean value of the whole D/H data sample available to date (15 measurements) gives a conservative value of the primordial deuterium abundance (D/H) p = (2.55 ± 0.19) × 10 −5 which is in good agreement with the prediction of analysis of the cosmic microwave background radiation for the standard Big Bang nucleosynthesis. By means of the derived (D/H) p value the baryon density of the Universe Ω b h 2 = 0.0222 ± 0.0013 and the baryon-to-photon ratio η 10 = 6.09 ± 0.36 have been deduced. These values have confident intervals which are less stringent than that obtained for the Precision Sample and, thus, leave a broader window for new physics. The latter is particularly important in the light of the lithium problem.

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Section: Sources Of Uncertaintiesmentioning

confidence: 99%

The primordial deuterium abundance: subDLA system atz_abs = 2.437 towards the QSO J 1444+2919

Balashev¹,

Zavarygin²,

Ivanchik³

et al. 2016

Mon. Not. R. Astron. Soc.

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“…Processes in which deuterium could form are not sufficiently intensive to appreciably change its abundance (see, however, [64]). In this sense, any estimate of D/H is a lower limit for the primordial value (D/H) Pr .…”

Section: Primordial Dmentioning

confidence: 99%

H2/HD molecular clouds in the early universe. An independent means of estimating the baryon density of the universe

2015

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A review of molecular hydrogen H 2 absorption systems identified in quasar spectra is presented. The analysis of such systems allows the determination of the chemical composition of the interstellar medium and the physical conditions existing in the early Universe, about 10-12 billioin years ago. To date, 27 molecular hydrogen systems have been found, nine of which show HD lines. An independent method for estimating the baryon density of the Universe is described, and is based on the analysis of the relative abundances of H 2 and HD molecules. Among known H 2 /HD systems, only the two systems detected in Q1232+082 and Q0812+320 quasar spectra satisfy the condition of self-shielding of the absorbing cloud log N H2,HD 15. Under these conditions the local molecular fraction can reach unity, making it possible to estimate the relative deuterium abundance D/H using the ratio of the HD and H 2 column densities N (HD)/2N (H 2 ). The analysis of the column densities for these two systems yields D/H = HD/2H 2 = (3.26 ± 0.29) × 10 −5 . Comparison of this result with the prediction of BBN theory for D/H enables the determination of the baryon density of the Universe: Ω b h 2 = (0.0194 ± 0.0011). This is somewhat lower than the values Ω b h 2 = (0.0224 ± 0.0012) and (0.0221 ± 0.0003) obtained using other independent methods: (i) analysis of the relative D and H abundances in Lyman Limit Systems at high redshifts, and (ii) analysis of the anisotropy of the cosmic microwave background. Nevertheless, all three values agree within their 2σ errors.

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Influence of gamma-ray emission on the isotopic composition of clouds in the interstellar medium

Cited by 2 publications

References 53 publications

The primordial deuterium abundance: subDLA system atz_abs = 2.437 towards the QSO J 1444+2919

The primordial deuterium abundance: subDLA system atz_abs = 2.437 towards the QSO J 1444+2919

H2/HD molecular clouds in the early universe. An independent means of estimating the baryon density of the universe

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Influence of gamma-ray emission on the isotopic composition of clouds in the interstellar medium

Cited by 2 publications

References 53 publications

The primordial deuterium abundance: subDLA system atzabs = 2.437 towards the QSO J 1444+2919

The primordial deuterium abundance: subDLA system atzabs = 2.437 towards the QSO J 1444+2919

H2/HD molecular clouds in the early universe. An independent means of estimating the baryon density of the universe

Contact Info

Product

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The primordial deuterium abundance: subDLA system atz_abs = 2.437 towards the QSO J 1444+2919

The primordial deuterium abundance: subDLA system atz_abs = 2.437 towards the QSO J 1444+2919