On the use of sulphur as a tracer for abundances in galaxies. Issue 3 (12th February 2022)

• Record Type: Journal Article
• Authors: Díaz, Ángeles I; Zamora, S
• Is Part Of: Monthly notices of the Royal Astronomical Society. Volume 511:Issue 3(2022)
• Page Start: 4377
• Page End: 4392
• Publication Date: 2022-02-12
• Subjects: ISM: abundances -- H ii regions -- galaxies: abundances -- galaxies: ISM; Astronomy -- Periodicals; Periodicals; 520.5
• DOI: 10.1093/mnras/stac387
• Languages: English
• ISSNs: 0035-8711

Abstract

Abstract: 2+ We present a methodology for the use of sulphur as global metallicity tracer in galaxies, allowing performing a complete abundance analysis using only the red-to-near-infrared spectral region. We have applied it to a compilation of high-quality data split into two samples: H ii regions (DHR) in spiral and irregular galaxies, and dwarf galaxies dominated by a strong starburst (H ii Gal). Sulphur abundances have been derived by direct methods under the assumption of an ionization structure composed of two zones: an intermediate-ionization one where S ++ is originated, and a low-ionization one where S + is formed. Ionization correction factors (ICF) have been calculated from the Ar/Ar 3+ ratio and are shown to correlate with the hardness of the radiation field. Only about 10 per cent of the objects show S 3+ contributions to the total abundance larger than 30 per cent. A good correlation exists between sulphur abundance and ionizing temperature with low-metallicity objects being ionized by hotter stars. No correlation is found between ionization parameter and total S/H abundance. Most of the H ii Gal objects show S/O ratios below the solar value and a trend for increasing S/O ratios with increasing sulphur abundances, while DHR objects show S/O ratios larger than solar and a tendency for lower S/O ratios for higher metallicities. Finally, we present a calibration of the sulphur abundance through the S 23 parameter that remains single valued up to sulphur abundances well beyond the solar value. S 23 is independent of the ionization parameter and only weakly dependent on ionizing temperature.