Bibcode
Sánchez-Menguiano, L.; Sánchez, S. F.; Pérez, I.; Ruiz-Lara, T.; Galbany, L.; Anderson, J. P.; Krühler, T.; Kuncarayakti, H.; Lyman, J. D.
Bibliographical reference
Astronomy and Astrophysics, Volume 609, id.A119, 47 pp.
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2
2018
Journal
Citations
126
Refereed citations
113
Description
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 re,
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 αO/H =-0.10
± 0.03 dex /re. 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", rO/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
rO/H) and the outer flattening ( 1.5 rO/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.
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