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Marino, Raffaella Anna and Gil de Paz, Armando and Cardiel López, Nicolás and Castillo Morales, África and Catalán Torrecilla, Cristina and ..., otros. (2016) Outer-disk reddening and gas-phase metallicities: The CALIFA connection. Astronomy & Astrophysics, 585 . ISSN 1432-0746
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Official URL: http://dx.doi.org/10.1051/0004-6361/201526986
Abstract
We study, for the first time in a statistically significant and well-defined sample, the relation between the outer-disk ionized-gas metallicity gradients and the presence of breaks in the surface brightness profiles of disk galaxies. Sloan Digital Sky Survey (SDSS) g′- and r′-band surface brightness, (g′ – r′) color, and ionized-gasoxygen abundance profiles for 324 galaxies within the Calar Alto Legacy Integral Field Area (CALIFA) survey are used for this purpose. We perform a detailed light-profile classification, finding that 84% of our disks show down- or up-bending profiles (Type II and Type III, respectively), while the remaining 16% are well fitted by one single exponential (Type I). The analysis of the color gradients at both sides of this break shows a U-shaped profile for most Type II galaxies with an average minimum (g′ − r′) color of ~0.5 mag and an ionized-gas metallicity flattening associated with it only in the case of low-mass galaxies. Comparatively, more massive systems show a rather uniform negative metallicity gradient. The correlation between metallicity flattening and stellar mass for these systems results in p-values as low as 0.01. Independent of the mechanism having shaped the outer light profiles of these galaxies, stellar migration or a previous episode of star formation in a shrinking star-forming disk, it is clear that the imprint in their ionized-gas metallicity was different for low- and high-mass Type II galaxies. In the case of Type III disks, a positive correlation between the change in color and abundance gradient is found (the null hypothesis is ruled out with a p-value of 0.02), with the outer disks of Type III galaxies with masses ≤10^10 M_⊙ showing a weak color reddening or even a bluing. This is interpreted as primarily due to a mass downsizing effect on the population of Type III galaxies that recently experienced an enhanced inside-out growth.
Item Type: | Article |
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Additional Information: | © ESO, 2015. |
Uncontrolled Keywords: | Galactic chemical evolution; Integral field spectroscopy; Oxygen abundance gradient; Star-forming galaxies; H II regions; Spiral galaxies; Cosmological simulations; Corotation radius; Stellar content; Local universe |
Subjects: | Sciences > Physics > Astrophysics Sciences > Physics > Astronomy |
ID Code: | 37334 |
Deposited On: | 25 Apr 2016 15:19 |
Last Modified: | 10 Dec 2018 15:05 |
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