The CALIFA survey across the Hubble sequence. Spatially resolved stellar population properties in galaxies

Author(s)

R. M. González Delgado, R. García-Benito, E. Pérez, R. Cid Fernandes, A. L. de Amorim, C. Cortijo-Ferrero, E. A. D. Lacerda, R. López Fernández, N. Vale-Asari, S. F. Sánchez, M. Mollá, T. Ruiz-Lara, P. Sánchez-Blázquez, C. J. Walcher, J. Alves, J. A. L. Aguerri, S. Bekeraité, J. Bland-Hawthorn, L. Galbany, A. Gallazzi, B. Husemann, J. Iglesias-Páramo, V. Kalinova, A. R. López-Sánchez, R. A. Marino, I. Márquez, J. Masegosa, D. Mast, J. Méndez-Abreu, A. Mendoza, A. del Olmo, I. Pérez, A. Quirrenbach, S. Zibetti

Abstract

Various different physical processes contribute to the star formation and stellar mass assembly histories of galaxies. One important approach to understanding the significance of these different processes on galaxy evolution is the study of the stellar population content of today's galaxies in a spatially resolved manner. The aim of this paper is to characterize in detail the radial structure of stellar population properties of galaxies in the nearby universe, based on a uniquely large galaxy sample, considering the quality and coverage of the data. The sample under study was drawn from the CALIFA survey and contains 300 galaxies observed with integral field spectroscopy. These cover a wide range of Hubble types, from spheroids to spiral galaxies, while stellar masses range from M

_{Black star}∼ 10

⁹to 7 × 10

¹¹M

_⊙. We apply the fossil record method based on spectral synthesis techniques to recover the following physical properties for each spatial resolution element in our target galaxies: the stellar mass surface density (μ

_{Black star}), stellar extinction (A

_V), light-weighted and mass-weighted ages ('log age'

_L, 'log age'

_M), and mass-weighted metallicity ('log Z

_{Black star}'

_M). To study mean trends with overall galaxy properties, the individual radial profiles are stacked in seven bins of galaxy morphology (E, S0, Sa, Sb, Sbc, Sc, and Sd). We confirm that more massive galaxies are more compact, older, more metal rich, and less reddened by dust. Additionally, we find that these trends are preserved spatially with the radial distance to the nucleus. Deviations from these relations appear correlated with Hubble type: earlier types are more compact, older, and more metal rich for a given M

_{Black star}, which is evidence that quenching is related to morphology, but not driven by mass. Negative gradients of 'log age'

_Lare consistent with an inside-out growth of galaxies, with the largest 'log age'

_Lgradients in Sb-Sbc galaxies. Further, the mean stellar ages of disks and bulges are correlated and with disks covering a wider range of ages, and late-type spirals hosting younger disks. However, age gradients are only mildly negative or flat beyond R ∼ 2 HLR (half light radius), indicating that star formation is more uniformly distributed or that stellar migration is important at these distances. The gradients in stellar mass surface density depend mostly on stellar mass, in the sense that more massive galaxies are more centrally concentrated. Whatever sets the concentration indices of galaxies obviously depends less on quenching/morphology than on the depth of the potential well. There is a secondary correlation in the sense that at the same M

_{Black star}early-type galaxies have steeper gradients. The μ

_{Black star}gradients outside 1 HLR show no dependence on Hubble type. We find mildly negative 'log Z

_{Black star}'

_Mgradients, which are shallower than predicted from models of galaxy evolution in isolation. In general, metallicity gradients depend on stellar mass, and less on morphology, hinting that metallicity is affected by both - the depth of the potential well and morphology/quenching. Thus, the largest 'log Z

_{Black star}'

_Mgradients occur in Milky Way-like Sb-Sbc galaxies, and are similar to those measured above the Galactic disk. Sc spirals show flatter 'log Z

_{Black star}'

_Mgradients, possibly indicating a larger contribution from secular evolution in disks. The galaxies from the sample have decreasing-outward stellar extinction; all spirals show similar radial profiles, independent from the stellar mass, but redder than E and S0. Overall, we conclude that quenching processes act in manners that are independent of mass, while metallicity and galaxy structure are influenced by mass-dependent processes.

Organisation(s)

Department of Astrophysics

External organisation(s)

Instituto de Astrofísica de Andalucía (CSIC), Universidade Federal de Santa Catarina, Universidad Nacional Autonoma de Mexico, Centro de Investigaciones Energeticas Medioambientales y Tecnológica, Universidad de Granada, Universidad Autónoma de Madrid, Leibniz-Institut für Astrophysik Potsdam, Institute of Astrophysics of the Canary Islands, The University of Sydney, Universidad de Chile, European Southern Observatory (Germany), University of Alberta, Australian Astronomical Observatory, Universidad Complutense de Madrid, Centro Brasileiro de Pesquisas Físicas (CBPF), University of St. Andrews, Landessternwarte Königstuhl (LSW), INAF - Osservatorio Astrofisico di Arcetri

Journal

Astronomy & Astrophysics

Volume

581

No. of pages

44

ISSN

0004-6361

Publication date

09-2015

Peer reviewed

Yes

Austrian Fields of Science 2012

103003 Astronomy, 103004 Astrophysics

Keywords

ASJC Scopus subject areas

Astronomy and Astrophysics, Space and Planetary Science

Portal url

https://ucrisportal.univie.ac.at/en/publications/0fe7cb09-8054-4c43-a0cf-94d9bc320a2f