Sulfur abundances in the Galactic bulge and disk

Abstract

Context. The measurement of $\alpha$-elements abundances provides a powerful tool to put constraints on chemical evolution and star formation history of galaxies. The majority of studies on the $\alpha$-element Sulfur (S) are focused on local stars, making S behavior in other environments an astronomical topic yet to be analyzed. Aims. The investigation of S in the Galactic bulge has only recently been 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 S abundances of 74 dwarf and sub-giant stars in the Galactic bulge, 21 and 30 F and G thick and thin disk stars. We performed 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 $-2<$[Fe/H]$<$0.6, by spectrosynthesis or line equivalent widths. Results. We confirm that S behaves like 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], until reaching [S/Fe]$\sim 0$ at 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 more rapid formation and chemical evolution of the Galactic bulge than the disk.

14 pages, 9 figures, 4 tables

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