Oxygen and zinc abundances in 417 Galactic bulge red giants

TL;DR

This study measures oxygen and zinc abundances in 417 Galactic bulge red giants to understand the bulge's chemical evolution, star formation history, and nucleosynthesis processes, comparing results with models and literature data.

Contribution

It provides a large, homogeneous dataset of oxygen and zinc abundances in bulge giants, including intercomparisons with higher-resolution spectra and literature, advancing understanding of bulge chemical evolution.

Findings

Oxygen-to-iron ratios indicate rapid star formation in the bulge.

Zinc behaves as an alpha-element, especially in metal-poor stars.

Results align with chemodynamical models of bulge evolution.

Abstract

Oxygen and zinc in the Galactic bulge are key elements for the understanding of the bulge chemical evolution. Oxygen-to-iron abundance ratios provide a most robust indicator of the star formation rate and chemical evolution of the bulge. Zinc is enhanced in metal-poor stars, behaving as an $\alpha$-element, and its production may require nucleosynthesis in hypernovae. Most of the neutral gas at high redshift is in damped Lyman-alpha systems (DLAs), where Zn is also observed to behave as an alpha-element. The aim of this work is the derivation of the alpha-element oxygen, together with nitrogen, and the iron-peak element zinc abundances in 417 bulge giants, from moderate resolution (R~22,000) FLAMES-GIRAFFE spectra. For stars in common with a set of UVES spectra with higher resolution (R~45,000), the data are intercompared. The results are compared with literature data and chemodynamical models.