1. Isotopic abundance of carbon in the DLA towards QSO B1331+170
- Author
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Milaković, Dinko, Webb, John K., Molaro, Paolo, Lee, Chung-Chi, Jethwa, Prashin, Cupani, Guido, Murphy, Michael T., Welsh, Louise, D'Odorico, Valentina, Cristiani, Stefano, Santos, Ricardo Génova, Martins, Carlos J. A. P., Nunes, Nelson J., Schmidt, Tobias M., Pepe, Francesco A., Osorio, Maria Rosa Zapatero, Alibert, Yann, Hernández, J. I. González, Di Marcantonio, Paolo, Palle, Enric, Santos, Nuno C., and Rebolo, Rafael
- Subjects
Astrophysics - Astrophysics of Galaxies ,Astrophysics - Cosmology and Nongalactic Astrophysics - Abstract
Chemical evolution models predict a gradual build-up of $^{13}$C in the universe, based on empirical nuclear reaction rates and assumptions on the properties of stellar populations. However, old metal-poor stars within the Galaxy contain more $^{13}$C than is predicted, suggesting that further refinements to the models are necessary. Gas at high redshift provides important supplementary information at metallicities $-2\lesssim$ [Fe/H] $\lesssim-1$, for which there are only a few measurements in the Galaxy. We obtained new, high-quality, VLT/ESPRESSO observations of the QSO B1331+170 and used them to measure $^{12}$C/$^{13}$C in the damped Lyman-$\alpha$ system (DLA) at $z_{abs}=1.776$, with [Fe/H]=-1.27. AI-VPFIT, an Artificial Intelligence tool based on genetic algorithms and guided by a spectroscopic information criterion, was used to explore different possible kinematic structures of the carbon gas. Three hundred independent AI-VPFIT models of the absorption system were produced using pre-set $^{12}$C/$^{13}$C values, ranging from 4 to 500. Our results show that $^{12}$C/$^{13}$C$=28.5^{+51.5}_{-10.4}$, suggesting a possibility of $^{13}$C production at low metallicity., Comment: 11 pages, 6 figures. Three appendices. To appear in MNRAS
- Published
- 2024