Aims. We present the B-, V- and K-band surface photometry catalogs obtained running the automatic software GASPHOT on galaxies from the WINGS cluster survey having isophotal area larger than 200 pixels. The catalogs can be downloaded at the Centre de Donnees Astronomiques de Strasbourg (CDS). Methods. We outline the GASPHOT performances and compare our surface photometry with that obtained by SExtractor, GALFIT and GIM2D. This analysis is aimed at providing statistical information about the accuracy generally achieved by the softwares for automatic surface photometry of galaxies. Results. For each galaxy and for each photometric band the GASPHOT catalogs provide the parameters of the Sersic law best-fitting the luminosity profiles. They are: the sky coordinates of the galaxy center (R:A:; DEC:), the total magnitude (m), the semi-major axis of the effective isophote (Re), the Sersic index (n), the axis ratio (b=a) and a flag parameter (QFLAG) giving a global indication of the fit quality. The WINGS-GASPHOT database includes 41,463 galaxies in the B-band, 42,275 in the V-band, and 71,687 in the K-band. We find that the bright early-type galaxies have larger Sersic indices and effective radii, as well as redder colors in their center. In general the effective radii increase systematically from the K- to the V- and B-band. Conclusions. The GASPHOT photometry turns out to be in fairly good agreement with the surface photometry obtained by GALFIT and GIM2D, as well as with the aperture photometry provided by SExtractor. The main advantages of GASPHOT with respect to other tools are: (i) the automatic finding of the local PSF; (ii) the short CPU time of execution; (iii) the remarkable stability against the choice of the initial guess parameters. All these characteristics make GASPHOT an ideal tool for blind surface photometry of large galaxy samples in wide-field CCD mosaics.

G. La Mura∗,a D. Bindoni,b S. Ciroi,b V. Cracco,b P. Rafanelli,b L. Vaona,b R. D’Abruscoc aInstitut für Astround Teilchenphysik, Universität Innsb ruck Technikerstrasse 25/8, A-6020 Innsbruck, Austria bDipartimento di Fisica e Astronomia, Università di Padova Vicolo dell’Osservatorio 3, I-35122 Padova, Italy cHigh Energy Astrophysics Division, Harvard-Smithsonian C enter for Astrophysics 60 Garden Street, Cambridge, Massachusetts

We have analyzed the growth curves and the surface brightness light profiles of the clusters of the WINGS sample (Fasano et al. 2006) in the B and V bands, measuring the effective radii, the effective surface brightnesses and the total luminosities of our clusters. The similarly of the radial surface brightness profiles of early-type galaxies (ETGs) and clusters indicate that within r(200) almost all clusters are virialized structures. The total luminosities L-B of clusters are found to correlate with the X-ray luminosity L-X, following approximately the same relation measured for galaxies by Eskridge et al. (1995). By coupling the photometric data with the central velocity dispersions, derived from the radial velocities of the galaxies measured by Cava et al. (2009), we were able to fit the fundamental plane (FP) of clusters of galaxies. We find that it has approximately the same slope of the FPs of early-type galaxies (ETGs) and globular clusters (GCs), but differs from them in the zero-point. This behavior can be easily explained in terms of a different contribution of dark matter (DM). (C) 2013 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim

We search for massive and compact galaxies (superdense galaxies, hereafter SDGs) at z = 0.03-0.11 in the Padova-Millennium Galaxy and Group Catalogue, a spectroscopically complete sample representative of the general field population of the local universe. We find that compact galaxies with radii and mass densities comparable to high-z massive and passive galaxies represent 4.4% of all galaxies with stellar masses above 3 x 10(10) M-circle dot, yielding a number density of 4.3 x 10(-4) h(3) Mpc(-3). Most of them are S0s (70%) or ellipticals (23%), are red, and have intermediate-to-old stellar populations, with a median luminosity-weighted age of 5.4 Gyr and a median mass-weighted age of 9.2 Gyr. Their velocity dispersions and dynamical masses are consistent with the small radii and high stellar mass estimates. Comparing with the WINGS sample of cluster galaxies at similar redshifts, the fraction of SDGs is three times smaller in the field than in clusters, and cluster SDGs are on average 4 Gyr older than field SDGs. We confirm the existence of a universal trend of smaller radii for older luminosity-weighted ages at fixed galaxy mass. As a consequence, the median mass-size relation shifts toward smaller radii for galaxies with older stars, but the effect is much more pronounced in clusters than in the field. Our results show that, on top of the well-known dependence of stellar age on galaxy mass, the luminosity-weighted age of galaxies depends on galaxy compactness at fixed mass and, for a fixed mass and radius, on environment. This effect needs to be taken into account in order not to overestimate the evolution of galaxy sizes from high to low z. Our results and hierarchical simulations suggest that a significant fraction of the massive compact galaxies at high z have evolved into compact galaxies in galaxy clusters today. When stellar age and environmental effects are taken into account, the average amount of size evolution of individual galaxies between high and low z is mild, a factor similar to 1.6.

By exploiting the data base of early-type galaxy (ETG) members of the WINGS survey of nearby clusters, we address here the long debated question of the origin and shape of the Fundamental Plane (FP). Our data suggest that different physical mechanisms concur in shaping and 'tilting' the FP with respect to the virial plane (VP) expectation. In particular, a 'hybrid solution' in which the structure of galaxies and their stellar population are the main contributors to the FP tilt seems to be favoured. We find that the bulk of the tilt should be attributed to structural non-homology, while stellar population effects play an important but less crucial role. In addition, our data indicate that the differential FP tilt between the V and K band is due to a sort of entanglement between structural and stellar population effects, for which the inward steepening of colour profiles (V - K) tends to increase at increasing the stellar mass of ETGs. The same kind of analysis applied to the ATLAS3D and Sloan Digital Sky Survey (SDSS) data in common with WINGS (WSDSS throughout the paper) confirms our results, the only remarkable difference being the less important role that our data attribute to the stellar mass-to-light-ratio (stellar populations) in determining the FP tilt. The ATLAS3D data also suggest that the FP tilt depends as well on the dark matter (DM) fraction and on the rotational contribution to the kinetic energy (V-rot/sigma), thus again pointing towards the above-mentioned 'hybrid solution'. We show that the global properties of the FP, i.e. its tilt and tightness, can be understood in terms of the underlying correlation among mass, structure and stellar population of ETGs, for which, at increasing the stellar mass, ETGs become (on average) 'older' and more centrally concentrated. Finally, we show that a Malmquist-like selection effect may mimic a differential evolution of the mass-to-light ratio for galaxies of different masses. This should be taken into account in the studies investigating the amount of the so-called 'downsizing' phenomenon.

We present a study of galaxy sizes in the local Universe as a function of galaxy environment, comparing clusters and the general field. Galaxies with radii and masses comparable to high-z massive and compact galaxies represent 4.4 galaxies are 3 times more frequent in clusters than in the field. Most of them are early-type galaxies with intermediate to old stellar populations. There is a trend of smaller radii for older luminosity-weighted ages at fixed galaxy mass. We show the relation between size and luminosity-weighted age for galaxies of different stellar masses and in different environments. We compare with high-z data to quantify the evolution of galaxy sizes. We find that, once the progenitor bias due to the relation between galaxy size and stellar age is removed, the average amount of size evolution of individual galaxies between high- and low-z is mild, of the order of a factor 1.6.

The observed relationship between stellar mass and effective radius for early type galaxies, pointed out by many authors, is interpreted in the context of Clausius' virial maximum theory. In this view, it is strongly underlined that the key of the above mentioned correlation is owing to the presence of a deep link between cosmology and the existence of the galaxy Fundamental Plane. Then the ultimate meaning is: understanding visible mass - size correlation and/or Fundamental Plane means understanding how galaxies form. The mass - size relationship involves baryon (mainly stellar) mass and its typical dimension related to the light, but it gets memory of the cosmological mass variance at the equivalence epoch. The reason is that the baryonic component virializes by sharing virial energy in about equal amount between baryons and dark matter, this sharing depending, in turn, on the steepness of the dark matter distribution. The general strategy consists in using the two-component tensor virial theorem for determining the virialized baryonic configurations. A King and a Zhao density profile are assumed for the inner baryonic and the outer dark matter component, respectively, at the end of the relaxation phase. All the considerations are restricted to spherical symmetry for simplicity. The effect of changing the dark-to-baryon mass ratio, m, is investigated inside a LambdaCDM scenario. A theoretical mass - size relation is expressed for the baryonic component, which fits fairly well to the data from a recently studied galaxy sample. Finally, the play of intrinsic dispersion on the mass ratio, m, is discussed in the light of the cusp/core problem and some consequences are speculated about the existence of a limit, m_l, expected by the theory.

The existence of correlations between nuclear properties of galaxies, such as the mass of their central black holes, and larger scale features, like the bulge mass and luminosity, represent a fundamental constraint on galaxy evolution. Although the actual reasons for these relations have not yet been identified, it is widely believed that they could stem from a connection between the processes that lead to black hole growth and stellar mass assembly. The problem of understanding how the processes of nuclear activity and star formation can affect each other became known to the literature as the Starburst-AGN connection. Despite years of investigation, the physical mechanisms which lie at the basis of this relation are known only in part. In this work, we analyze the problem of star formation and nuclear activity in a large sample of galaxies. We study the relations between the properties of the nuclear environments and of their host galaxies. We find that the mass of the stellar component within the galaxies of our sample is a critical parameter, that we have to consider in an evolutionary sequence, which provides further insight in the connection between AGN and star formation processes.

Nuclear activity and star formation processes represent two key elements in the evolution of galaxies across the cosmic ages. In spite of very different physical backgrounds, several arguments suggest that they should be closely connected. On the basis of simple theoretical considerations, the transport of appreciable amounts of fuel to the AGN scale is very likely to trigger star formation in the gas. Young stellar populations, in their turn, are expected to affect the properties of the interstellar medium, leading to a complex balance of interactions among nuclear activity and star formation. This scenario is also supported by the observation of super-massive black holes and host galaxy properties, which strongly suggest a common evolutionary track. However, despite several years of extensive investigation, the relationship among the two processes still has to be properly explained. Here we provide a review of some of the most important observations, which are relevant to the issue of the connection among AGN and starburst events. Based on a wide sample of observations, we present an analysis of the spectral signatures connected with AGN and star formation activity. Expanding the concept of the distinction among star forming galaxies and the true active nuclei, we provide systematic evidence for a role of recent starburst events in the circum-nuclear regions of active galaxies and discuss the possibility of its influence onto the AGN environment. We also analyze the age, mass and metallicity properties of star-forming and active galaxies, illustrating that they are arranged in a sequence that is consistent with the identified relation.

In the Clausius' virial maximum theory (TCV) [Secco and Bindoni, NewA 14, 567 (2009)1 to explain the galaxy Fundamental Plane (FP) a natural explanation follows about the observed relationship between stellar mass and effective radius, M-* - r(e), for early type galaxies (ETGs). The key of this correlation lies in the deep link which has to exist between cosmology and the existence of the FP. The general strategy consists in using the two-component tensor virial theorem to describe the virial configuration of the baryonic component of mass M-B similar or equal to M-* embedded in a dark matter (DM) halo of mass M-D at the end of relaxation phase. In a ACDM flat cosmology, starting from variance at equivalence epoch, we derive some preliminary theoretical relationships, M-* - r(e), which are functions of mass ratio m = M-D/M-B. They appear to be in agreement with the trends extracted from the data of galaxy sample used by [Tortora et al., MNRAS 396, 1132 (2009)].

The theory of the Clausius' virial maximum proposed by Secco (2000, 2001, 2005) is based on the existence of a maximum in the Clausius' Virial potential energy of a baryonic component when it is completely embedded inside a dark matter (DM) halo. When this maximum is reached the baryonic inner component acquires a scale length in its own gravity field due to the induced effect on it from the dark matter gravitation. The existence of this special configuration among the infinity number of those an inner component may assume inside an outer DM halo is able to explain the typical scale relationships observed for the early type galaxies (ETGs) which derive from their lying on the Fundamental Plane (FP). To prove that we model an ETG in the following way: an inner baryonic component of stellar kind built-up by a King-model with a cut-off and a DM halo with a cored power law density profile. The two components, which are gravitationally interacting, settle on virial equilibrium after violent relaxation. The new improved model allows us to understand more deeply the dynamical reason of the FP existence and in particular why it has a tilt. The main puzzle may be also fully understood that is why the FP is degenerated with respect to the initial density perturbation spectrum in a CDM hierarchical clustering cosmological scenario.

The theory of the Clausius' Virial maximum to explain the fundamental plane (FP) proposed by Secco [Secco, L., 2000. NewA, 5, 403; Secco, L. 2001. NewA, 6, 339; Secco, L. 2005. NewA, 10, 439] is based on the existence of a maximum in the Clausius' Virial (CV) potential energy of a early type galaxy (ETG) stellar component when it is completely embedded inside a dark matter (DM) halo. At the first order approximation the theory was developed by modeling the two-components with two cored power-law density profiles. An higher level of approximation is now taken into account by developing the same theory when the stellar component is modeled by a King-model with a cut-off. Even if the DM halo density remains a cored power-law the inner component is now more realistic for the ETGs. The new formulation allows us to understand more deeply what is the dynamical reason of the FP tilt and in general how the CV theory may really be the engine to produce the FP main features. The degeneracy of FP in respect to the initial density perturbation spectrum may be now full understood in a CDM cosmological scenario. A possible way to compare the FPs predicted by the theory with those obtained by observations is also exemplified.

The problem of violent relaxation mechanism in collisionless systems from the point of view of the distribution function (DF) in μ-space is reviewed. The literature run starts from the seminal paper of Lynden-Bell [Lynden-Bell, D., 1967. MNRAS 136, 101] and is closed by that of the same author [Arad, I., Lynden-Bell, D., 2005. MNRAS 361, 385]. After some introductive sections on the stellar dynamical equilibria and on the Shannon’s information theory, the different approaches follow each accompanied with its criticism on the previous works. Different coarse-grained DFs proposed by different authors have been taken into account. It appears that for a collisionless gas of a unique mass specie there is not significant discrepancies among the different approaches which converge to the same DF at the end of relaxation process. The main problem is to avoid the non observed mass segregation in the case of multi-species composition, e.g., in a star-dominated galaxy component. On this topic the results are very different and are depending on the shape and size one chooses for μ-space tiles. A great effort has been spent into the visualization of the different partitions in phase-space in order to understand clearly from what the differences arise.

The dynamical theory of the Fundamental Plane (Secco 2005, e.g.) is based on the existence of a maximum in the Clausius Virial potential energy (CV) of a stellar component, V. when it is completely embedded inside a dark matter (DM) halo. At its first order approximation (linear approximation) the theory was developed by modeling the two components with two power-law density profiles and two homogeneous cores. To extend the theory to an higher order (non-linear) we explore the effect on an homogeneous stellar component due to a DM halo with selected Zhao' density profile (Zhao 1996) characterized by three exponents (alpha,beta,gamma), where gamma is the slope at r -> 0, beta at r -> infinity and a describes the transition region between the above mentioned limits. The aim is to compare the predictions of the theory in two special cases: (2,3,0) and (1,3,1), i.e. the NFW density profile (Navarro, Frenk & White 1996). We follow the general method proposed by Caimmi (1993) for two homoidally striated ellipsoids in virial equilibrium described by tensor virial equations extended to two components (Caimmi & Secco 1992). The role of the dark to bright mass ratio m and of the halo concentration CD in order to produce the maximum of CV in both cases are taken into account. The relevance of the slope at which the maximum appears inside the halo DM profile is also considered.

Numerical simulations, general dynamical considerations and some observations constrain in different way the inner asymptotic slope of the dark matter (DM) halo density profile. The dynamical theory of the Fundamental Plane (FP) based on the existence of a maximum in the Clausius' Virial potential energy (CV) of a galaxy stellar component which is completely embedded inside a DM halo, adds a contribution to the controversy in favour of a cored profile.

We present a panoramic review of several observational and theoretical aspects of the modern astrophysical research about the origin of the fundamental plane (FP) relation for early-type galaxies (ETGs). The discussion is focused on the problem of the tilt and the tightness of the FP, and on the attempts to derive the luminosity evolution of ETGs with redshift. Finally, a number of observed features in the FP are interpreted from the standpoint of a new theoretical approach based on the two-component tensor virial theorem.

Abstract As found in Secco (2000, 2001), the presence of a (non-baryonic) dark halo in large-scale celestial objects, can induce a scale length on the luminous spheroid through the occurrence of an unexpected maximum in the virial potential energy (Clausius Virial, CV). The above mentioned investigations were grounded on two cored power law density profiles, but the same result is shown to hold for more refined and realistic models.

Abstract To test the extension of the theory of the Fundamental Plane (FP) proposed by Secco (2000, 2001, 2005) to an higher order (non-linear) we explore the effect on an homogeneous stellar component due to a DM halo with a density profile characterized by an inner slope γ free and an outer slope −3, according to high resolution RCs of Sps (Garrido et al., 2004). The aim is to investigate the role of the dark to bright mass ratio m and of the halo concentration CD in order to produce the maximum of Clausius' Virial potential energy (CV). Particular attention is devoted to the slope of the density halo profile at the maximum location, to its height in comparison with the CV value when the two components coincide, Vn. For all models we choose γ = 0. We follow the general method proposed by Caimmi, 1993 for two striated ellipsoidals with Zhao-density profiles. Virial equilibrium is described by tensor virial equations extended to two components (Caimmi & Secco, 1992). Sequences of CV as function of the ratio baryonic to halo virial semi-axis, numerically performed for different values of m and CD, are taken into account.