Galaxies are a complex mix of stars, interstellar gas, dust, and dark matter, distributed in the bulge, disk, and halo. The present day structure and dynamics of these galaxy sub-components are intimately linked to their assembly and evolution over the age of the Universe. This project aims to establish observational constraints to models of galaxy formation and evolution, by resolving in time and space the properties of the stellar populations of galaxies in the local Universe. We use the fossil record that the stellar populations imprint in their galaxy spectra, and the full spectral synthesis technique to retrieve when and where the mass and metals were assembled as a function of look-back time. The scientific objectives are geared to understand: 1. The growth of spheroids and disks. 2. The cosmic evolution of the star formation in galaxies. 3. The quenching of the star formation in galaxies.
The project uses the integral field spectroscopic data from the CALIFA survey, designed to make a rational and efficient use of the singular and unique facility of the 3.5m telescope at the Calar Alto observatory. CALIFA is unique for this research because: a) it includes a large sample of galaxies, well distributed across the colour-magnitude diagram, covering a wide range of galaxy mass, and Hubble types (E, S0, and Spirals from Sa to Sd); b) it has a large FoV that allows to simultaneously compute the integrated and the spatially resolved stellar population properties; c) it covers the full rest-frame optical wavelength at intermediate spectral resolution, including the most relevant absorption diagnostics for stellar populations.
This dataset provides the legacy of an important and homogeneous database that together with our analysis allow us to get: (i) 2D maps and radial structures of the stellar mass surface density, extinction, age, metallicity, and star formation rate surface density as a function of the Hubble type. (ii) Multi-wavelength bulge/disk decomposition, allowing to derive the star formation history and stellar population properties separately for bulges and disks. (iii) 1D temporal curves of the growth of mass and metals as a function of radial distance for dwarf and massive galaxies; and the evolution of the mass-metallicity relation. (iv) 2D spatial and temporal maps of the star formation history of mergers and galaxies across the Hubble type to trace the radial dependence of the star formation laws of galaxies. (v) The radial structure of the quenching time for galaxies in the green valley to trace the evolution from the blue cloud to the red sequence.
Our group belongs to the CALIFA collaboration from the early beginning of the survey definition and preparation of the project, and forms a consolidated team within the collaboration, leading the CALIFA second data release. Further, we have already developed the computational tools for the analysis, thru a close collaboration between Florianópolis and Granada, with interchange of PhD young researchers, and months of working visits of the senior scientists between the two countries. This places our research in an advanced stage to produce high impact results, providing clues on the new 3D view of the internal properties of galaxies, that are critical to constrain models of galaxy formation and evolution.