Spectroscopic optical data (∼4200-6300 Å in the rest-frame) acquired during the monitoring of some QSOs seem to confirm that AGN spectra normally harden at higher luminosities. Focusing only on the global trend (i.e. comparing different objects), the implications in deriving luminosities using optical photometric data (through the K-correction) is briefly outlined here, as well as the result of its parameterization for calculating BH masses through the M$_{BH} \propto$ L$_V^\gamma$ (FWHM Hβ)2 virial relation.To search for other articles by the author(s) go to: http://adsabs.harvard.edu/abstract_service.html

In this contribution we present the detection of two WHIM filaments in the Chandra-LETG spectrum of Mkn 421. This spectrum has been obtained following 2 of our pre-approved Target of Opportunity requests to observe Blazars in outburst to efficiently ‘X-ray’ the IGM at high spectral resolution. These observations caught the source at the unprecedented levels of 60 and 40 mCrab in the soft X-ray (0.5-2 keV) band. We detect, for the first time, two WHIM filaments at redshifts of z=0.011 and z=0.027, respectively. Based on these two detections and on the upper limits on associated HI and OVI absorption as inferred from the HST and FUSE spectra of Mkn 421, we estimate a number of WHIM filaments per unit redshift, with He-like ion columns $N_{X} \gs 8 \times 10^{14}$ cm$^{-2}$ of $dN/dz = 67^{+88}_{-43}$, and a baryon mass density of $\Omega_b = 0.021^{+0.028}_{-0.014}$, virtually all of the ‘missing baryons’ at $z\lt1$.To search for other articles by the author(s) go to: http://adsabs.harvard.edu/abstract_service.html

We report the status of our study of the central region of M 83. Recently a binary mass concentration at the nucleus was suggested by Thatte et al. (2000), and we determined the possible position of the optically hidden mass concentration with 2D Hα kinematics. We continue our study of this region trough IR 3D spectroscopy performed with CIRPASS, attached to the Gemini South telescope. Almost 1500 spectra were obtained, centered in the wavelength 1.3 μm. The velocity field in a region of 13″ × 9″ around the optical nucleus is resolved, with 0.36″ (6.4 pc) sampling. We confirm that the optical nucleus of M 83 is not located at the most important center of symmetry of the velocity field. The largest black hole that could fit to the circular motion in this kinematic center should have a mass less than $2\times10^7M_{\odot}$.To search for other articles by the author(s) go to: http://adsabs.harvard.edu/abstract_service.html

We discuss the discovery of six bright Lyman break galaxy candidates in the Sloan Digital Sky Survey and the follow-up observations necessary to determine whether they are powered by star formation or by active galactic nuclei.To search for other articles by the author(s) go to: http://adsabs.harvard.edu/abstract_service.html

In this work we investigate the stellar population, metallicity distribution and ionized gas in the elliptical galaxy NGC 5044, using long-slit spectroscopy and a stellar population synthesis method. We found differences in the slope of FeI and Mg2 lines gradients, which suggests an enhancement of α elements, particularly towards the central region. The stellar population synthesis shows that the contribution, at λ5870, of the most metallic and old stellar population ($Z/Z_\odot \sim 0.0$ and 1010year) is dominant in NGC 5044. The presence of a non-thermal ionization source, such as a low-luminosity AGN and/or shock ionization, is implied by the large values of the ratio [NII]/Hα observed in all sampled regions. However, the emission lines observed in the external regions indicate the presence of an additional ionization source, probably hot, post-AGB stars.To search for other articles by the author(s) go to: http://adsabs.harvard.edu/abstract_service.html

We present spatially resolved X-ray spectra taken with the EPIC cameras of XMM-Newton of a sample of 17 cooling clusters and three non-cooling clusters for comparison. The deprojected spectra are analyzed with a single-temperature model. All cooling clusters show a central decrement of the average temperature, most of them of a factor of $\sim$2. Three clusters show a weak temperature decrement, while two others have a very strong temperature decrement. We investigate the role of heat conduction by electrons and find that the theoretically predicted conductivity rates are not high enough to balance radiation losses.To search for other articles by the author(s) go to: http://adsabs.harvard.edu/abstract_service.html

We discuss evidence in local, present-day clusters of galaxies (from the ENACS survey) about the way in which those clusters have evolved and about the evolutionary relationships between the galaxies of different morphological types in them. This evidence is complementary to that obtained from the study of clusters at intermediate and high redshifts. We argue that the spatial distribution and the kinematics of the various types of galaxies in and outside substructures support the following picture.

The elliptical and S0 galaxies have been around for a long time and have obtained an isotropic velocity distribution. The spatial distribution and kinematics of the early spirals are consistent with the idea that many of their kind have transformed into an S0, but that they have survived, most likely because of their velocities. The distribution and kinematics of the late spirals are consistent with a picture in which they have been accreted fairly recently. They have mildly radial orbits and hardly populate the central regions, most likely because they suffer tidal disruption. Finally, the distribution and kinematics of the galaxies in substructures, when taken at face value, imply tangential velocity anisotropy for these galaxies, but this result may be (partly) due to the procedure by which these galaxies are selected. A first attempt to take the effects of selection into account shows that isotropic (or even mildly radial) orbits of subcluster galaxies cannot be excluded.To search for other articles by the author(s) go to: http://adsabs.harvard.edu/abstract_service.html

To understand cluster formation and evolution it is important to understand the evolution of cluster substructure. The work described here focuses upon a set of fully self-consistent numerical simulations within a $\Lambda$CDM cosmology. Within the simulations we follow in detail the temporal and spatial properties of individually tracked satellite galaxies. The host galaxy clusters were chosen to sample a variety of formation histories, ages, and triaxialities. Despite their obvious differences, we find striking similarities within the associated substructure populations. Namely, the satellite galaxy orbital distributions are indistinguishable between the galaxy clusters.To search for other articles by the author(s) go to: http://adsabs.harvard.edu/abstract_service.html

We present our project on galaxy evolution in the environment of distant rich clusters aiming at disentangling the importance of specific interaction and galaxy transformation processes from the hierarchical evolution of field galaxies. Spatially resolved MOS spectra were gained with VLT/FORS to analyze the internal kinematics of disk galaxies. First results are shown for the clusters MS 1008.1–1224 ($z=0.30$), Cl 0303+1706 ($z=0.42$), and Cl 0413–6559 ($z=0.51$). Out of 35 late-type cluster members, 13 galaxies exhibit a rotation curve of the universal form rising in the inner region and passing over into a flat part. The other members have peculiar kinematics. The 13 cluster galaxies for which a maximum rotation velocity could be derived are distributed in the Tully-Fisher diagram very similarly to field galaxies from the FORS Deep Field with corresponding redshifts. The same is true for seven non-cluster galaxies observed in the cluster fields. The TF-cluster spirals do not show any significant luminosity evolution as might be expected from certain phenomena specific to clusters. Contrary to that, the disturbed kinematics of the non–TF cluster spirals indicate ongoing or recent interaction processes.To search for other articles by the author(s) go to: http://adsabs.harvard.edu/abstract_service.html

We quantify the importance of mass accretion during AGN phases in the growth of supermassive black holes (BH) by comparing the mass function of black holes in the local universe with that expected from AGN relics, which are black holes grown entirely with mass accretion during AGN phases. The local BH mass function (BHMF) is estimated by applying the well-known correlations between BH mass, bulge luminosity and stellar velocity dispersion to galaxy luminosity and velocity functions. The density of BHs in the local universe is $\rhoBH = 4.6_{-1.4}^{+1.9}\, h_{0.7}^2 \rhoBHunits$. The relic BHMF is derived from the continuity equation with the only assumption that AGN activity is due to accretion onto massive BHs and that merging is not important. We find that the relic BHMF at z = 0 is generated mainly at z<3. Moreover, the BH growth is anti-hierarchical in the sense that smaller BHs ($M_{BH}<10^{7}M_\odot$) grow at lower redshifts (z<1) with respect to more massive ones (z∼1−3). Unlike previous work, we find that the BHMF of AGN relics is perfectly consistent with the local BHMF indicating the local BHs were mainly grown during AGN activity. This agreement is obtained while satisfying, at the same time, the constraints imposed from the X-ray background. The comparison with the local BHMF also suggests that the merging process is not important in shaping the relic BHMF, at least at low redshifts (z<3). Our analysis thus suggests the following scenario: local black holes grew during AGN phases in which accreting matter was converted into radiation with efficiencies ε = 0.04−0.16 and emitted at a fraction λ = 0.1−1.7 and emitted at a fraction λ = 0.1−1.7 of the Eddington luminosity. The average total lifetime of these active phases ranges from $\simeq 4.5\times 10^{8}$ yr for $M_{BH}<10^{8}M_\odot$ to $\simeq 1.5\xten{8}$ yr for $M_{BH}>10^{9}M_\odot$.To search for other articles by the author(s) go to: http://adsabs.harvard.edu/abstract_service.html

Local HII galaxies present a Fundamental Plane of [L–σ] where either the equivalent width of Hβ or the oxygen abundance O/H act as a second parameter. These relations are powerful cosmological distance indicators since emission line galaxies may be found to high redshifts, though some caution must be taken till systematic effects are better understood.To search for other articles by the author(s) go to: http://adsabs.harvard.edu/abstract_service.html

We present spectroscopic observations of the peculiar system AM1003-435, which is composed of two strong interacting galaxies, and numerical simulations of the encounter between the galaxies, following the dynamical evolution of the stellar and gaseous components.To search for other articles by the author(s) go to: http://adsabs.harvard.edu/abstract_service.html

We present results from an imaging and spectroscopic study of the dust properties of Seyfert galaxies in the 1-10 μm range. The data are compared to state of the art models of torus emission to constrain geometrical and physical properties of the obscuring medium.To search for other articles by the author(s) go to: http://adsabs.harvard.edu/abstract_service.html

Wide-angle, moderately deep redshift surveys such as that conducted as part of the Sloan Digital Sky Survey (SDSS) allow study of the relationship between the structural elements of the large-scale distribution of galaxies – including groups, cluster, superclusters, and voids – and the dependence of galaxy formation and evolution on these enviroments. We present a progress report on mapping efforts with the SDSS and discuss recently constructed catalogs of clusters, voids, and void galaxies, and evidence for a $420h^{-1}$Mpc supercluster or “Great Wall.” Analysis of multi-band photometry and moderate-resolution spectroscopy from the SDSS reveals environmental dependence of the star formation history of galaxies that extends over more than a factor of 100 in density, from clusters all the way to the deep interiors of voids. On average, galaxies in the rarified environments of voids exhibit bluer colors, higher specific star formation rates, lower dust content, and more disk-like morphology than objects in denser regions. This trend persists in comparisons of samples in low vs. high-density regions with similar luminosity and morphology, thus this dependence is not simply an extension of the morphology-density relation. Large-scale modulation of the halo mass function and the temperature of the intergalactic medium might explain this dependence of galaxy evolution on the large-scale environment.To search for other articles by the author(s) go to: http://adsabs.harvard.edu/abstract_service.html

Wide field imaging is key to understanding the build-up of distant clusters and their galaxy population. By focusing on the so far unexplored outskirts of clusters, where infalling galaxies first hit the cluster potential and the hot intracluster medium, we can help separate cosmological field galaxy evolution from that driven by environment. I present a selection of recent advancements in this area, with particular emphasis on Hubble Space Telescope wide field imaging, for its superior capability to deliver galaxy morphologies and precise shear maps of distant clusters.To search for other articles by the author(s) go to: http://adsabs.harvard.edu/abstract_service.html

MRC B1221–423 is a powerful, nearby (z = 0.17) compact radio source, which lies within the envelope of a galaxy which is undergoing a tidal interaction with a companion. Broad-band optical/NIR colours show evidence of several distinct episodes of star formation. The evidence points to this being a radio source “caught in the act” of its first ignition.To search for other articles by the author(s) go to: http://adsabs.harvard.edu/abstract_service.html

We study AGN jet formation by means of exact solutions of the relativistic magnetohydrodynamic equations. This is an original extension in Schwarzchild's metric of previous meridionally self-similar models. The outflow is mainly thermally driven to high asymptotic speeds from the central region where the escape speed is also high. The jet solutions are magnetically collimated on the sub-parsec scale.To search for other articles by the author(s) go to: http://adsabs.harvard.edu/abstract_service.html

We present the preliminary result of our project, consisting in studying the properties of a large sample of galaxy clusters. The Münster Red Sky Survey, which is a large galaxy catalogue covering an area of about 5000 square degrees on the southern hemisphere, serves as our observational basis. It is complete up to $r_F=18^m.3$. Creation of a cluster catalogue is the first step of our investigation. We propose to use the 2D Voronoi tessellation technique for identifying galaxy clusters in this 2D catalogue. Points with high values of the inverse Voronoi tessel area will be regarded as galaxy cluster centroids. We show that this approach works correctly.To search for other articles by the author(s) go to: http://adsabs.harvard.edu/abstract_service.html

VLT and NTT spectra are used to examine the nuclear and extended coronal line emission in a sample of well-known Seyfert 1 and 2 galaxies. The excellent spatial resolution obtained with VLT allowed us to map [Si VI] 1.963μm and [Si VII] 2.48μm on scales of up to 20 pc. Coronal line emission, extended to distances of ∼102 pc, is detected in some of the lines analyzed, particularly in [Fe X] 6374Å, [Fe XI] 7891Å, and [Si VII] 2.48μm. Most coronal lines are strongly asymmetric towards the blue and broader than low-ionization lines. This result is particularly important for Circinus, where previous observations have failed to detect larger widths for high-ionization lines. Photoionization models are used to investigate the physical conditions and continuum luminosities necessary to produced the observed coronal emission. We found that an ionization parameter U>0.10 is necessary to reproduce the observations, although the clouds should be located at a distance <30 pc from the central engine.To search for other articles by the author(s) go to: http://adsabs.harvard.edu/abstract_service.html

We provide the first direct lifting of the mass/anisotropy degeneracy for a cluster of galaxies, by jointly fitting the line of sight velocity dispersion and kurtosis profiles of the Coma cluster, assuming an NFW tracer density profile, a generalized-NFW dark matter profile and a constant anisotropy profile. We find that the orbits in Coma must be quasi-isotropic, and find a mass consistent with previous analyses, but a concentration parameter 50% higher than expected in cosmological $N$-body simulations. We then test the accuracy of our method on realistic non-spherical systems with substructure and streaming motions, by applying it to the ten most massive structures in a cosmological $N$-body simulation. We find that our method yields fairly accurate results on average (within 20%), although with a wide variation (factor 1.7 at 1$\sigma$) for the concentration parameter, with decreased accuracy and efficiency when the projected mean velocity is not constant with radius.To search for other articles by the author(s) go to: http://adsabs.harvard.edu/abstract_service.html