Arm–interarm gas abundance variations explored with MUSE: the role of spiral structure in the chemical enrichment of galaxies

Abstract

Spiral arms are the most characteristic features of disc galaxies, easily distinguishable due to their association with ongoing star formation. However, the role of spiral structure in the chemical evolution of galaxies is unclear. Here we explore gas-phase abundance variations between arm and interarm regions for a sample of 45 spiral galaxies using high spatial resolution VLT/MUSE Integral Field Spectroscopy data. We report the presence of more metal-rich H ii regions in the spiral arms with respect to the corresponding interarm regions for a large subsample of galaxies (45 − 65% depending on the adopted calibrator for the abundance derivation). A small percentage of the sample is observed to display the opposite trend, that is, more metal-poor H ii regions in the spiral arms compared to that of the interarms (5−20% depending on the calibrator). We investigate the dependence of the variations with three galaxy properties: the stellar mass, the presence of bars, and the flocculent/grand design appearance of spiral arms. In all cases, we observe that the arm-interarm abundance differences are larger (positive) in more massive and grand-design galaxies. This is confirmed by an analogous spaxel-wise analysis, which also shows a noticeable effect of the presence of galactic bars, with barred systems presenting larger (positive) arm-interarm abundance variations than unbarred systems. The comparison of our results with new predictions from theoretical models exploring the nature of the spirals would highly impact on our knowledge on how these structures form and affect their host galaxies.

Measuring the mixing scale of the ISM within nearby spiral galaxies

“…Preliminary results from the first eight completed galaxies in the PHANGS-MUSE survey (Kreckel et al 2019, hereafter Paper I) reveal that half exhibit significant azimuthal variations, and suggest that spiral arms play a role in organizing and mixing the ISM. These statistics have been recently confirmed with a larger sample of 45 disc galaxies (Sánchez-Menguiano et al 2020).…”

3D gas-phase elemental abundances across the formation histories of Milky Way-mass galaxies in the FIRE simulations: initial conditions for chemical tagging

“…However, they found that gas elements quickly exchange abundances after migrating, leading to small azimuthal dispersions in abundance. Sánchez-Menguiano et al (2020) found that azimuthal variations in abundances are stronger in galaxies with stronger bars and grand-design spirals, which supports non-axisymmetric structure driving azimuthal inhomogeneities.…”

“…Pilyugin et al 2014;Sánchez-Menguiano et al 2016;Belfiore et al 2017;Poetrodjojo et al 2018). Furthermore, some observations show azimuthal variations (Sánchez et al 2015;Vogt et al 2017;Ho et al 2017Ho et al , 2018Kreckel et al 2019;Kreckel et al 2020;Sánchez-Menguiano et al 2020), while others show no azimuthal variations within measurement uncertainty ( 0.05 dex) (e.g. Cedrés & Cepa 2002;Zinchenko et al 2016).…”

A geostatistical analysis of multiscale metallicity variations in galaxies [I]: Introduction and comparison of high-resolution metallicity maps to an analytic metal transport model

“…Erroz-Ferrer et al 2019;Sánchez-Menguiano et al 2019;Wang & Lilly 2021), or the presence of spiral arms (e.g. Ho et al 2017;Sánchez-Menguiano et al 2020). In this study we will consider the process mean to depend solely on the metallicity gradient, as described in Equation 3.…”