Metrópolis: reconversiones y pensamientos transgresores: hipótesis irreverente sobre una ciudad posible: una estrategia para la consolidación de espacio público y la vivienda de interés social en la Ciudad Autónoma de Buenos Aires del SXXI: escenario de intervención sobre la reconversión de los espacios del fútbol

Peer Reviewe

Ultra deep sub-kpc view of nearby massive compact galaxies

Using Gemini North telescope ultra deep and high resolution (sub-kpc) K-band adaptive optics imaging of a sample of 4 nearby (z~0.15) massive (~10^{11}M_sun) compact (R<1.5 kpc) galaxies, we have explored the structural properties of these rare objects with an unprecedented detail. Our surface brightness profiles expand over 12 magnitudes in range allowing us to explore the presence of any faint extended envelope on these objects down to stellar mass densities ~10^{6} M_sun/kpc^{2} at radial distances of ~15 kpc. We find no evidence for any extended faint tail altering the compactness of these galaxies. Our objects are elongated, resembling visually S0 galaxies, and have a central stellar mass density well above the stellar mass densities of objects with similar stellar mass but normal size in the present universe. If these massive compact objects will eventually transform into normal size galaxies, the processes driving this size growth will have to migrate around 2-3x10^{10}M_sun stellar mass from their inner (R<1.7 kpc) region towards their outskirts. Nearby massive compact galaxies share with high-z compact massive galaxies not only their stellar mass, size and velocity dispersion but also the shape of their profiles and the mean age of their stellar populations. This makes these singular galaxies unique laboratories to explore the early stages of the formation of massive galaxies.Comment: Accepted for publication in ApJ Letter. Version revised to match the accepted versio

Early type galaxies have been the predominant morphological class for massive galaxies since only z~1

Present-day massive galaxies are composed mostly of early-type objects. It is unknown whether this was also the case at higher redshifts. In a hierarchical assembling scenario the morphological content of the massive population is expected to change with time from disk-like objects in the early Universe to spheroid-like galaxies at present. In this paper we have probed this theoretical expectation by compiling a large sample of massive (M_{stellar}>10^{11} h_{70}^{-2} M_{Sun}$) galaxies in the redshift interval 0 < z < 3. Our sample of 1082 objects comprises 207 local galaxies selected from SDSS plus 875 objects observed with the HST belonging to the POWIR/DEEP2 and GNS surveys. 639 of our objects have spectroscopic redshifts. Our morphological classification is performed as close as possible to the optical restframe according to the photometric bands available in our observations both quantitatively (using the Sersic index as a morphological proxy) and qualitative (by visual inspection). Using both techniques we find an enormous change on the dominant morphological class with cosmic time. The fraction of early-type galaxies among the massive galaxy population has changed from ~20-30% at z~3 to ~70% at z=0. Early type galaxies have been the predominant morphological class for massive galaxies since only z~1.Comment: 24 pages, 11 figures, 7 tables, MNRAS accepted, acknowledgement adde