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This study probes the chemical abundances of the neutron-capture elements cerium and neodymium in the inner Milky Way from an analysis of a sample of 2000 stars in the Galactic Bulge/bar spatially contained within |X₆₀₋|<5 kpc, |Y₆₀₋|<3. 5 kpc, and |Z₆₀₋|<1 kpc, and spanning metallicities between -2. 0Fe/H+0. 5. We classify the sample stars into low- or high-Mg/Fe populations and find that, in general, values of Ce/Fe and Nd/Fe increase as the metallicity decreases for the low- and high-Mg/Fe populations. Ce abundances show a more complex variation across the metallicity range of our Bulge-bar sample when compared to Nd, with the r-process dominating the production of neutron-capture elements in the high-Mg/Fe population (Ce/Nd<0. 0). We find a spatial chemical dependence of Ce and Nd abundances for our sample of Bulge-bar stars, with low- and high-Mg/Fe populations displaying a distinct abundance distribution. In the region close to the center of the MW, the low-Mg/Fe population is dominated by stars with low Ce/Fe, Ce/Mg, Nd/Mg, Nd/Fe, and Ce/Nd ratios. The low Ce/Nd ratio indicates a significant contribution in this central region from r-process yields for the low-Mg/Fe population. The chemical pattern of the most metal-poor stars in our sample suggests an early chemical enrichment of the Bulge dominated by yields from core-collapse supernovae and r-process astrophysical sites, such as magneto-rotational supernovae.
Sales-Silva et al. (Thu,) studied this question.