Sulfur abundances in the Galactic bulge and disk

Context. The measurement of a-element abundances provides a powerful tool for placing constraints on the chemical evolution and star formation history of galaxies. The majority of studies on the a-element sulfur (S) are focused on local stars, making S behavior in other environments an astronomical topic that is yet to be explored in detail. Aims. The investigation of S in the Galactic bulge was recently considered for the first time. This work aims to improve our knowledge on S behavior in this component of the Milky Way. Methods. We present the S abundances of 74 dwarf and sub-giant stars in the Galactic bulge, along with 21 and 30 F and G thick- and thin-disk stars, respectively. We performed a local thermodynamic equilibrium analysis and applied corrections for non-LTE on high resolution and high signal-to-noise UVES spectra. S abundances were derived from multiplets 1, 6, and 8 in the metallicity range of - 2 < [Fe/H] < 0.6, by spectrosynthesis or line equivalent widths. Results. We confirm that the behavior of S resembles that of an alpha-element within the Galactic bulge. In the [S/Fe] versus [Fe/H] diagram, S presents a plateau at low metallicity, followed by a decreasing of [S/Fe] with the increasing of [Fe/H], before reaching [S/Fe] similar to 0 at a super-solar metallicity. We found that the Galactic bulge is S-rich with respect to both the thick- and thin-disks at - 1 < [Fe/H] < 0.3, supporting a scenario of more rapid formation and chemical evolution in the Galactic bulge than in the disk.

Automated summary

This study aims to improve our understanding of the behavior of sulfur in the Galactic bulge by analyzing the abundances of sulfur in multiple stars. The results confirm that sulfur behaves like an alpha-element in the Galactic bulge and suggest that the Galactic bulge is sulfur-rich compared to the disk.