Exploring the synergies of [O\,II]λ3727 with MUSE spectroscopy in PHANGS H II regions
Abstract
Spatially resolved maps of gas-phase metallicity provide key constraints on the chemical enrichment and mixing processes that drive galaxy evolution, but measurements based only on strong lines remain highly uncertain and dependent on emission-line coverage. In this work, we present a joint analysis of SITELLE observations, covering the [O II]λλ3726,3729 doublet, with PHANGS-MUSE spectroscopy covering 4800-9300 Angstroms, including Hβ, [O III]λ4959,5007, [N II]λ6584, Hα, [S II]λλ6716,6731, and [S III]λ9069, within five nearby spiral galaxies. By combining these data, we construct a homogeneous catalog of emission-line fluxes for 604 ionized nebulae, 556 of which are classified as H II regions. This enables a comparison of eight widely used strong-line metallicity calibrations, five new strong-line calibrations, and an investigation of ionization-parameter diagnostics. We recover known systematic offsets among calibrations, but also find that many exhibit very low scatter, less than 0.03-0.04 dex, in radial metallicity gradients. We find that [S III]/[S II] exhibits minimal secondary dependence on metallicity or extinction, suggesting that it may be a more robust tracer of ionization parameter than [O III]/[O II]. No significant outliers are identified in O/H or N/O within the sampled regions, indicating internally consistent abundance trends across the inner disks probed by our data. We provide a publicly available catalog of all measured emission-line fluxes, designed to support future investigations, including temperature modeling and strong-line abundance calibrations.
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