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oai:docta.ucm.es:20.500.14352/244402024-10-03T12:02:08Zcom_20.500.14352_14col_20.500.14352_15

Marino, Raffaella Anna Gil De Paz, Armando Sánchez, S. F. Sánchez Blázquez, Patricia Cardiel López, Nicolás Castillo Morales, María África Pascual Ramírez, Sergio Vílchez, J. Kehrig, C. Mollá, M. Mendez Abreu, J. Catalán Torrecilla, Cristina Florido, E. Perez, I. Ruiz Lara, T. Ellis, S. López Sánchez, Á. R. González Delgado, R. M. De Lorenzo Cáceres, A. García Benito, R. Galbany, L. Zibetti, S. Cortijo, C. Kalinova, V. Mast, D. Iglesias Páramo, J. Papaderos, P. Walcher, C. J. Bland Hawthorn, J. CALIFA Team 2023-06-18T06:51:55Z 2023-06-18T06:51:55Z 2016-01 1432-0746 10.1051/0004-6361/201526986 https://hdl.handle.net/20.500.14352/24440 http://dx.doi.org/10.1051/0004-6361/201526986 http://arxiv.org/abs/1509.07878 http://www.aanda.org/ 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. eng open access Outer-disk reddening and gas-phase metallicities: The CALIFA connection journal article