On The Nature of Fossil Galaxy Groups (2009)
La Barbera, F., De Carvalho, R. R., De La Rosa, I. G., Sorrentino, G., Gal, R. R., Kohl-Moreira, J. L.
We present a new sample of 25 fossil groups (FGs) at z < 0.1, along with a control sample of seventeen bright ellipticals located in non-fossil systems. Both the global properties of FGs (e.g. X-ray...
Lopes, P. A. A., De Carvalho, R. R., Kohl-Moreira, J. L., Jones, C.
We use SDSS data to investigate the scaling relations of 127 NoSOCS and 56 CIRS galaxy clusters at low redshift ($z \le 0.10$). We show that richness and both optical and X-ray luminosities are...
The Northern Sky Optical Cluster Survey. III. A Cluster Catalog Covering PI Steradians (2009)
Gal, R. R., Lopes, P. A. A., De Carvalho, R. R., Kohl-Moreira, J. L., Capelato, H. V., Djorgovski, S. G.
We present the complete galaxy cluster catalog from the Northern Sky Optical Cluster Survey, a new, objectively defined catalog of candidate galaxy clusters at z ≾ 0.25 drawn from the Digitized...
On the Nature of Fossil Galaxy Groups: Are they really fossils ? (2008)
La Barbera, F., De Carvalho, R. R., De La Rosa, I. G., Sorrentino, G., Gal, R. R., Kohl-Moreira, J. L.
We use SDSS-DR4 photometric and spectroscopic data out to redshift z~0.1 combined with ROSAT All Sky Survey X-ray data to produce a sample of twenty-five fossil groups (FGs), defined as bound systems...
The Northern Sky Optical Cluster Survey III: A Cluster Catalog Covering Pi Steradians (2008)
Gal, R. R., Lopes, P. A. A., De Carvalho, R. R., Kohl-Moreira, J. L., Capelato, H. V., Djorgovski, S. G.
We present the complete galaxy cluster catalog from the Northern Sky Optical Cluster Survey, a new, objectively defined catalog of candidate galaxy clusters at z
Cosmography with Galaxy Clusters (2008)
Soares-Santos, M., De Carvalho, R. R., La Barbera, F., Lopes, P. A. A., Annis, J.
In the present work we focus on future experiments using cluster abundance observations to constraint the Dark Energy equation of state parameter, w. To obtain tight constraints from this kind of...
NoSOCS in SDSS. I. Sample Definition and Comparison of Mass Estimates (2008)
Lopes, P. A. A., De Carvalho, R. R., Kohl-Moreira, J. L., Jones, C.
We use Sloan Digital Sky Survey (SDSS) data to investigate galaxy cluster properties of systems first detected within DPOSS. With the high quality photometry of SDSS we derived new photometric...
2DPHOT: A Multi-purpose Environment for the Two-dimensional Analysis of Wide-field Images (2008)
La Barbera, F., De Carvalho, R. R., Kohl-Moreira, J. L., Gal, R. R., Soares-Santos, M., Capaccioli, M., ...
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...
Evidence for overdensity around zem > 4 quasars from the proximity effect (2007)
Guimarães, R., Petitjean, P., Rollinde, E., De Carvalho, R. R., Djorgovski, S. G., Srianand, R., ...
We study the density field around zem > 4 quasars using high-quality medium spectral resolution Echelle Spectrograph and Imager–Keck spectra ( R∼ 4300 , signal-to-noise ratio (S/N) > 25) of 45...
Truncated Star Formation in Compact Groups of Galaxies: A Stellar Population Study (2006)
De La Rosa, I. G., De Carvalho, R. R., Vazdekis, A., Barbuy, B.
We present the results of a study comparing the stellar populations in the elliptical galaxies of Hickson Compact Groups (HCGs) with those in low density environments. Three different population...
Lopes, P. A. A., De Carvalho, R. R., Capelato, H. V., Gal, R. R., Djorgovski, S. G., Brunner, R. J., ...
We present a comparison of optical and X-ray properties of galaxy clusters in the northern sky. We determine the recovery rate of X-ray detected clusters in the optical as a function of richness,...
The DPOSS II compact group survey: first spectroscopically confirmed candidates (2006)
Pompei, E., De Carvalho, R. R., Iovino, A.
This paper presents the results of a pilot redshift survey of 18 candidate compact groups from the distant DPOSS survey that extends the available surveys of compact groups of galaxies to z ~0.2 in...
Ferreras, I., Pasquali, A., De Carvalho, R. R., De La Rosa, I. G., Lahav, O.
(Abridged) Environmental differences in the stellar populations of early-type galaxies are explored using principal component analysis (PCA), focusing on differences between elliptical galaxies in...
Color Gradients in Early-type Galaxies: Dependence on Environment and Redshift (2005)
La Barbera, F., De Carvalho, R. R., Gal, R., Busarello, G., Merluzzi, P., Capaccioli, M., ...
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...
A Catalog of Distant Compact Groups Using DPOSS (2005)
De Carvalho, R. R., Goncalves, T. S., Iovino, A., Kohl-Moreira, J. L., Gal, R. R., Djorgovski, S. G.
In this paper we present an objectively defined catalog of 459 small, high density groups of galaxies out to z~0.2 in a region of 6260 square degrees in the northern sky derived from the Digitized...
Morphology of low-redshift compact galaxy clusters I. Shapes and radial profiles (2005)
Strazzullo, V., Paolillo, M., Longo, G., Puddu, E., Djorgovski, S. G., De Carvalho, R. R., ...
The morphology of clusters of galaxies may be described with a set of parameters which contain information about the formation and evolutionary history of these systems. In this paper we present a...
Lopes, P. A. A., De Carvalho, R. R., Gal, R. R., Djorgovski, S. G., Odewahn, S. C., Mahabal, A. A., ...
We present an optically selected galaxy cluster catalog from ~ 2,700 square degrees of the Digitized Second Palomar Observatory Sky Survey (DPOSS), spanning the redshift range 0.1 < z < 0.5,...
Merging of Low-Mass Systems and the Origin of the Fundamental Plane (2004)
Evstigneeva, E. A., De Carvalho, R. R., Ribeiro, A. L., Capelato, H. V.
We present a new set of dissipationless N-body simulations to examine the feasibility of creating bright ellipticals (following the Kormendy relation) by hierarchically merging present-day early-type...
Peculiar Broad Absorption Line Quasars found in DPOSS (2003)
Brunner, Robert J., Hall, Patrick B., Djorgovski, S. George, Gal, R. R., Mahabal, A. A., Lopes, P. A. A., ...
With the recent release of large (i.e., > hundred million objects), well-calibrated photometric surveys, such as DPOSS, 2MASS, and SDSS, spectroscopic identification of important targets is no longer...
Gal, R. R., De Carvalho, R. R., Lopes, P. A. A., Djorgovski, S. G., Brunner, R. J., Mahabal, A. A., ...
We present a new, objectively defined catalog of candidate galaxy clusters based on the galaxy catalogs from the Digitized Second Palomar Observatory Sky Survey (DPOSS). This cluster catalog, derived...
The Digitized Second Palomar Observatory Sky Survey (DPOSS) II: Photometric Calibration (2002)
Gal, R. R., De Carvalho, R. R., Odewahn, S. C., Djorgovski, S. G., Mahabal, A. A., Brunner, R. J., ...
We present the photometric calibration technique for the Digitized Second Palomar Observatory Sky Survey (DPOSS), used to create seamless catalogs of calibrated objects over large sky areas. After...
The Fundamental Plane of Elliptical Galaxies in Compact Groups (2001)
De La Rosa, I. G., De Carvalho, R. R., Zepf, S.
We present a study focusing on the nature of compact groups through the study of their elliptical galaxies. We determine velocity dispersions ($\sigma$) for 18 18 bright elliptical galaxies located...
Exploration of Large Digital Sky Surveys (2000)
Djorgovski, S. G., Brunner, R. J., Mahabal, A. A., Odewahn, S. C., De Carvalho, R. R., Gal, R. R., ...
We review some of the scientific opportunities and technical challenges posed by the exploration of the large digital sky surveys, in the context of a Virtual Observatory (VO). The VO paradigm will...
Searches for Rare and New Types of Objects (2000)
Djorgovski, S. G., Mahabal, A. A., Brunner, R. J., Gal, R. R., Castro, S., De Carvalho, R. R., ...
Systematic exploration of the observable parameter space, covered by large digital sky surveys spanning a range of wavelengths, will be one of the primary modes of research with a Virtual Observatory...
Margoniner, V. E., De Carvalho, R. R., Gal, R. R., Djorgovski, S. G.
We examine the Butcher-Oemler effect and its cluster richness dependence in the largest sample studied to date: 295 Abell clusters. We find a strong correlation between cluster richness and the...
The Palomar Abell Cluster Optical Survey I: Photometric Redshifts for 431 Abell Clusters (2000)
Gal, R. R., De Carvalho, R. R, Brunner, R., Odewahn, S. C., Djorgovski, S. G.
This paper presents photometric redshifts for 431 Abell clusters imaged as part of the Palomar Abell Cluster Optical Survey (PACOS), of which 236 are new redshi fts. We have obtained moderately deep,...
Photometric Properties of 47 Clusters of Galaxies: I. The Butcher-Oemler Effect (2000)
Margoniner, V. E., De Carvalho, R. R.
We present gri CCD photometry of 44 Abell clusters and 4 cluster candidates. Twenty one clusters in our sample have spectroscopic redshifts. Fitting a relation between mean g, r and i magnitudes, and...
Automated search for LSB galaxies (1999)
Sabatini, S., Scaramella, R., Testa, V., Andreon, S., Longo, G., Djorgovski, G., ...
Low Surface Brightness Galaxies (LSBGs) today constitute the less known fraction of galaxies: their number density and their physical properties (e.g. luminosity, colour, dynamics) are still largely...
The Luminosity Function of 24 Abell Clusters from the CRoNaRio catalogues (1999)
Paolillo, M., Andreon, S., Longo, G., Puddu, E., Piranomonte, S., Scaramella, R., ...
We present the composite luminosity function of galaxies for 24 Abell clusters studied in our survey of the Northern Hemisphere, using DPOSS data in the framework of the CRoNaRio collaboration. Our...
An automatic procedure to extract galaxy clusters from CRoNaRio catalogs (1999)
Puddu, E., Andreon, S., Longo, G., Paolillo, M., Scaramella, R., Testa, V., ...
We present preliminary results of a simple peak finding algorithm applied to catalogues of galaxies, extracted from the Second Palomar Sky Survey in the framework of the CRoNaRio project. All...
The Multiplicity Function of groups of galaxies from CRoNaRio catalogues (1999)
De Filippis, E., Longo, G., Andreon, S., Scaramella, R., Testa, V., De Carvalho, R. R., ...
The projected multiplicity function of galaxies gives (per square degree) the density of galaxy aggregates formed by N members. We use the CRoNaRio matched catalogues to derive the low N (N
Quasar-Marked Protoclusters and Biased Galaxy Formation (1999)
Djorgovski, S. G., Odewahn, S. C., Gal, R. R., Brunner, R., De Carvalho, R. R.
We report on the current status of our search for protoclusters around quasars at z > 4. While the search is still very incomplete, clustered companion galaxies are found in virtually every case...
The Palomar Digital Sky Survey (DPOSS) (1998)
Djorgovski, S. G., Gal, R. R., Odewahn, S. C., De Carvalho, R. R., Brunner, R., Longo, G., ...
We describe DPOSS, a new digital survey of the northern sky, based on the POSS-II photographic sky atlas. The survey covers the entire sky north of delta = -3 deg in 3 bands, calibrated to the Gunn...
Systematic Variations in Age and Metallicity Along the Early-Type Galaxy Sequence (1998)
Pahre, M. A., Djorgovski, S. G., De Carvalho, R. R.
The form of the early-type galaxy scaling relation (the Fundamental Plane or FP) is a direct indicator of the underlying physical origins for the galaxy sequence. Observed properties of the FP...
Environments of Redshift Survey Compact Groups of Galaxies (1998)
Barton, E. J., De Carvalho, R. R., Geller, M. J.
Redshift Survey Compact Groups (RSCGs) are tight knots of N >= 3 galaxies selected from the CfA2+SSRS2 redshift survey. The selection is based on physical extent and association in redshift space...
Pahre, M. A., De Carvalho, R. R., Djorgovski, S. G.
The physical origins of the Fundamental Plane (FP) scaling relations are investigated for early-type galaxies observed at optical and near-infrared wavelengths. The slope for the FP is shown to...
Near-Infrared Imaging of Early-Type Galaxies III. The Near-Infrared Fundamental Plane (1998)
Pahre, M. A., Djorgovski, S. G., De Carvalho, R. R.
Near-infrared imaging data on 251 early-type galaxies in clusters and groups are used to construct the near-infrared Fundamental Plane (FP) r_eff ~ sigma_0^1.53 _eff^-0.79. The slope of the FP...
Data-Mining a Large Digital Sky Survey: From the Challenges to the Scientific Results (1997)
Djorgovski, S. G., De Carvalho, R. R., Odewahn, S. C., Gal, R. R., Roden, J., Stolorz, P., ...
The analysis and an efficient scientific exploration of the Digital Palomar Observatory Sky Survey (DPOSS) represents a major technical challenge. The input data set consists of 3 Terabytes of pixel...
Cataloging of the Digitized POSS-II, and Some Initial Scientific Results From It (1996)
Djorgovski, S. G., De Carvalho, R. R., Gal, R. R., Pahre, M. A., Scaramella, R., Longo, G.
We are conducting an effort to catalog all sources detected in the digitized POSS-II (DPOSS). This is now becoming an international collaboration including Caltech and the Observatories of Rome and...
HCG 16: A High Concentration of Active Galaxies in the Nearby Universe (1996)
Ribeiro, A. L. B., De Carvalho, R. R., Coziol, R., Capelato, H. V., Zepf, S. E.
In the course of an extensive campaign to measure radial velocities of galaxies in a selected sample of compact groups photometrically studied by de Carvalho et al. (1994), we report the discovery of...
Pahre, M. A., Djorgovski, S. G., De Carvalho, R. R.
We use the intercept of the elliptical galaxy radius--surface brightness (SB) relation at a fixed metric radius as the standard condition for the Tolman SB test of the universal expansion. We use...
The Near-Infrared Fundamental Plane of Elliptical Galaxies (1995)
Pahre, M. A., Djorgovski, S. G., De Carvalho, R. R.
We present results from a near-infrared $K$-band imaging survey of 59 elliptical galaxies in five nearby clusters. We measure photometric parameters for each galaxy using surface photometry and draw...
Southern Binary Galaxies. I. a Sample of Isolated Pairs (1994)
Soares, D. S. L., De Souza, R. E., De Carvalho, R. R.
A catalogue of binary galaxies with 621 pairs has been determined by applying a surface density enhancement procedure to {\it The Surface Photometry Catalogue of the ESO-Uppsala Galaxies}. The method...