Francesco Barbera

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This work deals with the evolution of the relation between half-light (effective) radius, re, and mean surface brightness, <μ>e, (known as Kormendy relation) at intermediate redshifts. A large sample of spheroids (N ∼ 230) in the three clusters of galaxies A 209 at z = 0.21, AC118 at z = 0.31, and EIS 0048 at z = 0.64 is analyzed by using ground-based data.(More)
Photometric redshifts (photo-z’s) are fundamental in galaxy surveys to address different topics, from gravitational lensing and dark matter distribution to galaxy evolution. The Kilo Degree Survey (KiDS), i.e. the ESO public survey on the VLT Survey Telescope (VST), provides the unprecedented opportunity to exploit a large galaxy dataset with an exceptional(More)
We describe 2DPHOT, a general purpose analysis environment for source detection and analysis in deep wide-field images. 2DPHOT is an automated tool to obtain both integrated and surface photometry of galaxies in an image, to perform reliable star-galaxy separation with accurate estimates of contamination at faint flux levels, and to estimate completeness of(More)
We present an analysis of star-formation and nuclear activity in galaxies as a function of both luminosity and environment in the fourth data release of the Sloan Digital Sky Survey (SDSS DR4). Using a sample of 27 753 galaxies in the redshift range 0.005<z<0.037 that is &90% complete to Mr = −18.0 we find that the EW(Hα) distribution is strongly bimodal,(More)
We present a detailed description of the Voronoi Tessellation (VT) cluster finder algorithm in 2+1 dimensions, which improves on past implementations of this technique. The need for cluster finder algorithms able to produce reliable cluster catalogs up to redshift 1 or beyond and down to 10 solar masses is paramount especially in light of upcoming surveys(More)
We present a detailed description of the Voronoi Tessellation (VT) cluster finder algorithm in 2+1 dimensions, which improves on past implementations of this technique. The need for cluster finder algorithms able to produce reliable cluster catalogs up to redshift 1 or beyond and down to 1013.5 solar masses is paramount especially in light of upcoming(More)
Color gradients in early-type galaxies contain valuable clues about their formation and evolutionary histories and mechanisms. We examine color gradients in 1,700 early-type galaxies in 159 galaxy clusters spanning a redshift range of 0.05 to 0.2. We find that color gradients strongly depend on the environment where galaxies reside, with steeper color(More)
We present a fundamental plane (FP) analysis of 141 early-type galaxies in the Shapley supercluster at z=0.049 based on spectroscopy from the AAOmega spectrograph at the AAT and photometry from the WFI on the ESO/MPI 2.2m telescope. The key feature of the survey is its coverage of low-mass galaxies down to σ∼50km s. We obtain a best-fitting FP relation re∝σ(More)
Structural parameters (half-light radius re, mean effective surface brightness 〈μ〉e, and Sersic index n, parameterizing the light profile shape) are derived for a sample of galaxies in the rich cluster AC118 at z = 0.31: so far the largest (N=93) sample of galaxies at intermediate-redshift with structural parameters measured in the near-infrared. The(More)
We present some preliminary results related to a project aimed at studying the evolution of the galaxy population in rich environments by means of the Color-Magnitude relation and of the Fundamental Plane. We derive the NIR and optical structural parameters for a sample of galaxies in the cluster AC118 at z=0.31. We prove that reliable structural parameters(More)