Spatially Resolved Star Formation Main Sequence of Galaxies in the Califa Survey

Abstract

The "main sequence of galaxies" - defined in terms of the total star formation rate ψ versus the total stellar mass M ∗ - is a well-studied tight relation that has been observed at several wavelengths and at different redshifts. All earlier studies have derived this relation from integrated properties of galaxies. We recover the same relation from an analysis of spatially resolved properties, with integral field spectroscopic (IFS) observations of 306 galaxies from the CALIFA survey. We consider the SFR surface density in units of log(M o yr-1 Kpc-2) and the stellar mass surface density in units of log(M o Kpc-2) in individual spaxels that probe spatial scales of 0.5-1.5 Kpc. This local relation exhibits a high degree of correlation with small scatter (σ = 0.23 dex), irrespective of the dominant ionization source of the host galaxy or its integrated stellar mass. We highlight (i) the integrated star formation main sequence formed by galaxies whose dominant ionization process is related to star formation, for which we find a slope of 0.81 ± 0.02; (ii) for the spatially resolved relation obtained with the spaxel analysis, we find a slope of 0.72 ± 0.04; and (iii) for the integrated main sequence, we also identified a sequence formed by galaxies that are dominated by an old stellar population, which we have called the retired galaxies sequence.Fil: Cano Díaz, M.. Universidad Nacional Autonoma de Mexico. Instituto de Astronomia; MéxicoFil: Sánchez, S. F.. Universidad Nacional Autonoma de Mexico. Instituto de Astronomia; MéxicoFil: Zibetti, S.. Osservatorio Astrofisico di Arcetri; Italia. Istituto Nazionale di Astrofisica; ItaliaFil: Ascasibar, Y.. Universidad Autónoma de Madrid; España. Consejo Superior de Investigaciones Científicas; EspañaFil: Bland Hawthorn, J.. University of Sydney; AustraliaFil: Ziegler, B.. Universidad de Viena; AustriaFil: González Delgado, R. M.. Instituto de Astrofísica de Andalucía; España. Consejo Superior de Investigaciones Científicas; EspañaFil: Walcher, C.J.. Gobierno de la República Federal de Alemania. Max Planck Institut für Astrophysik; AlemaniaFil: García Benito, Rubén. Instituto de Astrofísica de Andalucía; España. Consejo Superior de Investigaciones Científicas; EspañaFil: Mast, Damian. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Córdoba. Instituto de Astronomía Teórica y Experimental. Universidad Nacional de Córdoba. Observatorio Astronómico de Córdoba. Instituto de Astronomía Teórica y Experimental; ArgentinaFil: Mendoza Pérez, M. A.. Instituto de Astrofísica de Andalucía; España. Consejo Superior de Investigaciones Científicas; EspañaFil: Falcón Barroso, J.. Instituto de Astrofísica de Canarias; España. Universidad de La Laguna; EspañaFil: Galbany, Lluís. Millennium Institute of Astrophysics; Chile. Universidad de Chile; ChileFil: Husemann, Bernd. European Southern Observator; AlemaniaFil: Kehrig, C.. Instituto de Astrofísica de Andalucía; España. Consejo Superior de Investigaciones Científicas; EspañaFil: Marino, R. A.. Universidad Complutense de Madrid; España. ETH Zurich’s Institute for Astronomy; AlemaniaFil: Sánchez Blázquez, P.. Universidad Autónoma de Madrid; España. Pontificia Universidad Católica de Chile; ChileFil: López Cobá, C.. Universidad Nacional Autonoma de Mexico. Instituto de Astronomia; MéxicoFil: López Sánchez, Á. R.. Australian Astronomical Observatory; Australia. Macquarie University; AustraliaFil: Vílchez, J. M.. Instituto de Astrofísica de Andalucía; España. Consejo Superior de Investigaciones Científicas; Españ