@ARTICLE{2025OJAp....851253P,
       author = {{P{\'e}rez-Montero}, Enrique and {P{\'e}rez-D{\'\i}az}, Borja and {V{\'\i}lchez}, Jos{\'e} M. and {Zinchenko}, Igor A. and {Castrillo}, Asier and {Gavil{\'a}n}, Marta and {Zamora}, Sandra and {D{\'\i}az}, {\'A}ngeles I.},
        title = "{Sulphur abundances in star-forming regions from optical emission lines: A new approach based on photoionization models consistent with the direct method}",
      journal = {The Open Journal of Astrophysics},
     keywords = {Astrophysics of Galaxies},
         year = 2025,
        month = dec,
       volume = {8},
        pages = {51253},
     abstract = "{The derivation of sulphur chemical abundances in the gas-phase of star-
        forming galaxies is explored in this work, using the emission
        lines produced in these regions in the optical part of the
        spectrum and by means of photoionization models. We adapted the
        code HII-CHI-mistry to account for these abundances by
        implementing additional grids of models that assume a variable
        sulphur-to-oxygen abundance ratio, beyond the commonly assumed
        solar value. The addition of these models, and their use in a
        new iteration of the code allows us to use sulphur lines to
        precisely estimate the sulphur abundance, even in the absence of
        auroral lines. This approach aligns with the results from the
        direct method, and no additional assumptions about the
        ionization correction factor are needed, as the models directly
        predict the total sulphur abundance. We applied this new
        methodology to a large sample of star-forming regions from the
        MaNGA survey, and we explored the variation of the S/O ratio as
        a function of metallicity, making corrections for the
        significant contribution from diffuse ionized gas, which
        particularly affects the [SII] emission. Our results indicate no
        significant deviations from the solar S/O value in the range 8.0
        < 12+log(O/H) < 8.7, where the bulk of the MaNGA sample stays, ,
        \{but also with possible enhancements of sulphur at the high
        metallicity regime. This may be linked to the depletion of
        oxygen in the gas-phase due to its incorporation onto dust
        grains, as it remains when other metallicity indicators
        independent of this depletion, as S/H itself, are used instead.}",
          doi = {10.33232/001c.151253},
archivePrefix = {arXiv},
       eprint = {2506.14736},
 primaryClass = {astro-ph.GA},
       adsurl = {https://ui.adsabs.harvard.edu/abs/2025OJAp....851253P},
      adsnote = {Provided by the SAO/NASA Astrophysics Data System}
}