The star formation history of galaxies in 3D: The CALIFA perspective

Abstract. We spatially resolve the star formation history of 300 nearby galaxies from the CALIFA integral field survey to investigate: a) the radial structure and gradients of the present stellar populations properties as a function of the Hubble type; and b) the role played by the galaxy’s stellar mass and stellar mass surface density in governing the star formation history and metallicity enrichment of spheroids and disks. We apply the fossil record method based on spectral synthesis techniques to recover spatially and temporally resolved maps of stellar population properties of spheroid and spiral galaxies with mass from 109 to 7 × 1011 M. The individual radial profiles of the stellar mass surface density (µ?), stellar extinction (AV), luminosity weighted ages (〈log age〉L), and mass weighted metallicity (〈logZ?〉M) are stacked in seven bins of galaxy morphology (E, S0, Sa, Sb, Sbc, Sc and Sd). All these properties show negative gradients as a sign of the inside-out growth of massive galaxies. However, the gradients depend on the Hubble type in different ways. For the same galaxy mass, E and S0 galaxies show the largest inner gradients in µ?; while Andromeda-like galaxies (Sb with M? ∼ 1011 M) show the largest inner age and metallicity gradients. On average, spiral galaxies have a stellar metallicity gradient ∼-0.1 dex per half-light radius, in agreement with the value estimated fo