The shape of oxygen abundance profiles explored with MUSE: evidence for widespread deviations from single gradients

Abstract

We characterised the oxygen abundance radial distribution of a sample of 102 spiral galaxies observed with VLT/MUSE using the O3N2 calibrator. The high spatial resolution of the data allowed us to detect 14345 H ii regions with the same image quality as with photometric data, avoiding any dilution effect. We developed a new methodology to automatically fit the abundance radial profiles, finding that 55 galaxies of the sample exhibit a single negative gradient. The remaining 47 galaxies also display, as well as this negative trend, either an inner drop in the abundances (21), an outer flattening (10), or both (16), which suggests that these features are a common property of disc galaxies. The presence and depth of the inner drop depends on the stellar mass of the galaxies with the most massive systems presenting the deepest abundance drops, while there is no such dependence in the case of the outer flattening. We find that the inner drop appears always around 0.5 r e , while the position of the outer flattening varies over a wide range of galactocentric distances. Regarding the main negative gradient, we find a characteristic slope in the sample of α O/H = − 0.10 ± 0.03 dex/r e . This slope is independent of the presence of bars and the density of the environment. However, when inner drops or outer flattenings are detected, slightly steeper gradients are observed. This suggests that radial motions might play an important role in shaping the abundance profiles. We define a new normalisation scale ('the abundance scale length', r O/H ) for the radial profiles based on the characteristic abundance gradient, with which all the galaxies show a similar position for the inner drop (∼ 0.5 r O/H ) and the outer flattening (∼ 1.5 r O/H ). Finally, we find no significant dependence of the dispersion around the negative gradient with any property of the galaxies, with values compatible with the uncertainties associated with the derivation of the abundances.

H ii regions in the CALIFA survey: I. catalogue presentation

“…It will improve the detection of smaller (thus, fainter) H ii regions, the separation between adjacent regions, the definition of the DIG (and its different sources), and the overall decontamination of the DIG. New generation datasets, like the ones provided by MUSE (e.g., Sánchez-Menguiano et al 2018), andSITELLE (e.g., Rousseau-Nepton et al 2018), would require a re-evaluation of the proposed procedure, both for the detection of the H ii regions and for the decontamination by the DIG.…”

Stellar metallicity variations across spiral arms in disk galaxies with multiple populations

“…Hence their presence in a galaxy disk can generate differences in the mean chemical composition of stars in the arm and inter-arm regions. The existence of azimuthal variations in the chemical composition of stars has been well established by observations of different external spiral galaxies (e.g., Davies et al 2009;Li et al 2013;Ho et al 2017;Vogt et al 2017;Sánchez-Menguiano et al 2018). In the Milky Way disk, the detection of azimuthal metallicity patterns has become possible quite recently through large spectroscopic surveys.…”

The AMUSING++ Nearby Galaxy Compilation. I. Full Sample Characterization and Galactic-scale Outflow Selection

“…Although the instrument was designed to study intermediate/high redshift objects, MUSE is an excelent instrument to study with unprecedented detail, the structural components of nearby galaxies (e.g. Sánchez-Menguiano et al 2018).…”

“…So far it comprises ∼328 galaxies, being the core of the current compilation. This sample has been used to explore different science topics: (i) the radial profiles of the oxygen abundances in galaxies (Sánchez-Menguiano et al 2018), and its azimuthal variation (Sánchez et al 2015;Sánchez-Menguiano et al 2016); (ii) extended ionized gas fillaments associated to galaxy interactions (Prieto et al 2016a); (iii) the discovery of new strong lenses (Galbany et al 2018), and the optical counterpart of a radio-jet (López-Cobá et al 2017a); (iv) the derivation of main galaxy kinematic parameters such as velocity and velocity dispersion by different approaches (Bellocchi et al 2019); (v) individual type II supernova (Meza et al 2019); (vi) ionized gas tails (Boselli et al 2018); besides (vi) the local environment of supernovae, i.e., the major goal of the survey (Galbany et al 2016;Krühler et al 2017).…”