One Percent Determination of the Primordial Deuterium Abundance

Cooke, Ryan J.; Pettini, Max; Steidel, Charles C.

Abstract

We report a reanalysis of a near-pristine absorption system, located at a redshift ${z}_{\mathrm{abs}}=2.52564$ toward the quasar Q1243+307, based on the combination of archival and new data obtained with the HIRES echelle spectrograph on the Keck telescope. This absorption system, which has an oxygen abundance [O/H] = −2.769 ± 0.028 (sime1/600 of the solar abundance), is among the lowest metallicity systems currently known where a precise measurement of the deuterium abundance is afforded. Our detailed analysis of this system concludes, on the basis of eight D i absorption lines, that the deuterium abundance of this gas cloud is ${\mathrm{log}}_{10}({\rm{D}}/{\rm{H}})=-4.622\pm 0.015$, which is in very good agreement with the results previously reported by Kirkman et al., but with an improvement on the precision of this single measurement by a factor of ~3.5. Combining this new estimate with our previous sample of six high precision and homogeneously analyzed D/H measurements, we deduce that the primordial deuterium abundance is ${\mathrm{log}}_{10}{({\rm{D}}/{\rm{H}})}_{{\rm{P}}}=-4.5974\pm 0.0052$ or, expressed as a linear quantity, ${10}^{5}{({\rm{D}}/{\rm{H}})}_{{\rm{P}}}=2.527\pm 0.030;$ this value corresponds to a one percent determination of the primordial deuterium abundance. Combining our result with a big bang nucleosynthesis (BBN) calculation that uses the latest nuclear physics input, we find that the baryon density derived from BBN agrees to within 2σ of the latest results from the Planck cosmic microwave background data.

Citation

Cooke, R. J., Pettini, M., & Steidel, C. C. (2018). One Percent Determination of the Primordial Deuterium Abundance. Astrophysical Journal, 855(2), Article 102. https://doi.org/10.3847/1538-4357/aaab53

• Journal Article Type: Article
• Acceptance Date: Jan 27, 2018
• Online Publication Date: Mar 12, 2018
• Publication Date: Mar 12, 2018
• Deposit Date: Mar 20, 2018
• Publicly Available Date: Mar 23, 2018
• Journal: Astrophysical Journal
• Print ISSN: 0004-637X
• Electronic ISSN: 1538-4357
• Publisher: American Astronomical Society
• Peer Reviewed: Peer Reviewed
• Volume: 855
• Issue: 2
• Article Number: 102
• DOI: https://doi.org/10.3847/1538-4357/aaab53
• Public URL: https://durham-repository.worktribe.com/output/1337595
• Related Public URLs: https://arxiv.org/abs/1710.11129