Search

We search for and characterize substructures in the projected distribution of galaxies observed in the wide field CCD images of the 77 nearby clusters of the WIde-field Nearby Galaxy-cluster Survey (WINGS). This sample is complete in X-ray flux in the redshift range 0.04, Comment: A&A accepted - figure 6 is available from http://adlibitum.oats.inaf.it/ramella/WINGSfigs

This is the first paper of a series that will present data and scientific results from the WINGS project, a wide-field, multiwavelength imaging and spectroscopic survey of galaxies in 77 nearby clusters. The sample was extracted from the ROSAT catalogs with constraints on the redshift (0.0420). The global goal of the WINGS project is the systematic study of the local cosmic variance of the cluster population and of the properties of cluster galaxies as a function of cluster properties and local environment. This data collection will allow to define a local 'Zero-Point' reference against which to gauge the cosmic evolution when compared to more distant clusters. The core of the project consists of wide-field optical imaging of the selected clusters in the B and V bands. We have also completed a multi-fiber, medium resolution spectroscopic survey for 51 of the clusters in the master sample. In addition, a NIR (JK) survey of ~50 clusters and an H_alpha + UV survey of some 10 clusters are presently ongoing, while a very-wide-field optical survey has also been programmed. In this paper we briefly outline the global objectives and the main characteristics of the WINGS project. Moreover, the observing strategy and the data reduction of the optical imaging survey (WINGS-OPT) are presented. We have achieved a photometric accuracy of ~0.025mag, reaching completeness to V~23.5. Field size and resolution (FWHM) span the absolute intervals (1.6-2.7)Mpc and (0.7-1.7)kpc, respectively, depending on the redshift and on the seeing. This allows the planned studies to get a valuable description of the local properties of clusters and galaxies in clusters., Comment: 24 pages, 15 figures, Accepted by Astronomy and Astrophysics

Deep VLT optical spectroscopy, HST+ACS (GOODS) imaging and VLA observations are used to unveil the nature of a complete sample of 47 EROs with R-Ks>5 and Ks, 5 pages, 5 figures, to appear in Astronomy & Astrophysics Letters

In this work we build a detailed dynamic model for a S0 galaxy possibly hosting a central massive dark object (MDO). We show that the photometric profiles and the kinematics along the major and minor axes, including the h3 and h4 profiles, imply the presence of a central MDO of mass M = 1.5 - 9.7 10^8 solar masses, i.e. 0.3-2.8% of the mass derived for the stellar spheroidal component. Models without MDO are unable to reproduce the kinematic properties of the inner stars and of the rapidly rotating nuclear gas. The stellar population comprise of an exponential disc (27% of the light) and a diffuse spheroidal component (73% of the light) that cannot be represented by a simple de Vaucouleurs profile at any radius. The M/L ratios we found for the stellar components (respectively 3.3 and 6.6) are typical of those of disc and elliptical galaxies., Comment: 9 pages, 4 encapsulated postscript figures. Requires mn.sty, psfig.sty. Accepted for publication in MNRAS

We present an application of a new set of detailed, self-consistent, dynamical models for disc galaxies. We start from the hypothesis that each galaxy can be decomposed into a bulge, following the r1/4law, and a disc with an exponential projected density profile; and that the isodensity surfaces of each component can be represented by similar concentric spheroids. After taking into account both the asymmetric drift effects and the integration along the line of sight, we produce the rotational velocity and velocity-dispersion profile, andthe approximate shape of the line-of-sight velocity distributions for the stars as parameterized by the h3 and h4 coefficients of theGauss–Hermite expansion of the line profile. Photometric and kinematical data have been taken from the literature for the test case of the S0 galaxy NGC 5866, for which detailed stellar kinematical data are available at different positions across the galaxy. Apart from the innermost, dust-obscured regions of the galaxy, where observational effects are likely to be dominant, the model successfully reproduces the whole set of dynamical data available as well as giving a good fit to the photometry. The galaxy is shown to have an isotropic velocity-dispersion tensor, thus hinting at a dissipational formation process.

We present a comparison between the ionized gas and stellar kinematics for a sample of five early-to-intermediate disc galaxies. We measured the major axis V and σ radial profiles for both gas and stars, and the h 3 and h 4 radial profiles of the stars. We also derived from the R-band surface photometry of each galaxy the light contribution of their bulges and discs. In order to investigate the differences between the velocity fields of the sample galaxies we adopted the self-consistent dynamical model by Pignatelli and Galletta (1999), which takes into account the asymmetric drift effects, the projection effects along the line of sight and the non-Gaussian shape of the line profiles due to the presence of different components with distinct dynamical behaviour. We find for the stellar component a sizeable asymmetric drift effect in the inner regions of all the sample galaxies, as results from comparing their stellar rotation curves with the circular velocity predicted by the models. The galaxy sample is not wide enough to draw general conclusions. However, we have found a possible correlation between the presence of slowly rising gas rotation curves and the ratio of the bulge/disc half-luminosity radii, while there is no obvious correlation with the key parameter represented by the morphological classification, namely the bulge/disc luminosity ratio. Systems with a diffuse, dynamically hot component (bulge or lens) with a scale length comparable to that of the disc are characterized by slowly rising gas rotation curves. On the other hand, in systems with a small bulge the gas follows almost circular motions, regardless of the luminosity of the bulge itself. We noticed a similar behaviour also in the gas and stellar kinematics of the two early-type spiral galaxies modelled by Corsini et al.(1998).

We have performed VLT spectroscopy of an almost complete sample of 18 early-type galaxies with 0.88 < z < 1.3 plus two at z=0.67, selected from the K20 survey, and derived the velocity dispersion for 15+2 of them. By combining these data with HST and VLT images, we study the Fundamental Plane (FP), the Faber-Jackson and the Kormendy relations at z~1, and compare them with the local ones. The FP at z~1 keeps a remarkably small scatter, and shows both an offset and a rotation, which we interpret in terms of evolution of the mass-to-light ratio, and possibly of the size. We show evidence that the evolution rate depends on galaxy mass, being faster for less massive galaxies. We discuss the possible factors driving the evolution of spheroids and compare our results with the predictions of the hierachical models of galaxy formation., 14 pages, 15 figures, accepted by A&A

(Abridged) Context. This is the second paper of a series devoted to the WIde Field Nearby Galaxy-cluster Survey (WINGS). WINGS is a long term project which is gathering wide-field, multi-band imaging and spectroscopy of galaxies in a complete sample of 77 X-ray selected, nearby clusters (0.04=20deg). The main goal of this project is to establish a local reference for evolutionary studies of galaxies and galaxy clusters. Aims. This paper presents the optical (B,V) photometric catalogs of the WINGS sample and describes the procedures followed to construct them. Methods. We have constructed photometric catalogs based on wide-field images in B and V bands using SExtractor. Photometry has been performed on images in which large galaxies and halos of bright stars were removed after modeling them with elliptical isophotes. Results. We publish deep optical photometric catalogs (90% complete at V~21.7, which translates to ~M*(V)+6 at mean redshift), giving positions, geometrical parameters, and several total and aperture magnitudes for all the objects detected. For each field we have produced three catalogs containing galaxies, stars and objects of "unknown" classification (~16%)., Comment: Typo corrected in the initial of one of the authors (A. Cava). Accepted for publication in A&A. 19 pages, 4 tables, 11 figures. Catalogs will be available via CDS and WINGS website (http://web.oapd.inaf.it/wings/)

We use preliminary results of the WINGS survey (Fasano et al.) to obtain determinations of optical scaling relations for galaxy clusters. Passing from oneto twoparameter scaling relations we pay particular attention to the Kormendy relation (KR) and to the Fundamental Plane (FP) of galaxy clusters, comparing them with scaling relations of elliptical galaxies.

We present V —band surface photometry and major-axis kinematics of stars and ionized gas of three early-type spiral galaxies, namely NGC 772, NGC 3898 and NGC 7782. For each galaxy we built a self-consistent Jeans model for the stellar kinematics, adopting the light distribution of bulge and disc derived by means of a two-dimensional parametric photometric decomposition. This allowed us to investigate the presence of non-circular gas motions, and derive the mass distribution of luminous and dark matter in these objects. We found that the observed gas rotation corresponds to the circular velocity except for the innermost region (\( \left( {\left| r \right| \lesssim 8''} \right) \)”) of NGC 3898. This behaviour is quite common, although not ubiquitous, in the few bulge-dominated galaxies, for which dynamical modeling allows the comparison between the gas velocity and the circular speed. The mass is essentially traced by light in NGC 772 and NGC 7782, where gas rotation velocities were observed out to 0.2 R 25 and 0.6 R 25, respectively. For NGC 3898 we succeed in reproducing the observed gas rotation velocities, which extends out to 0.7 R 25, only taking into account the presence of a massive dark halo.

We present V-band surface photometry and major-axis kinematics of stars and ionized gas of three early-type spiral galaxies, namely NGC 772, NGC 3898 and NGC 7782. For each galaxy we built a self-consistent Jeans model for the stellar kinematics, adopting the light distribution of bulge and disc derived by means of a two-dimensional parametric photometric decomposition. This allowed us to investigate the presence of non-circular gas motions, and derive the mass distribution of luminous and dark matter in these objects. We found that the observed gas rotation corresponds to the circular velocity except for the innermost region (|r