In this short letter we present our new work on the coronal emission in a sample of AGN. We used the adaptive optics system NACO on the VLT to obtain high angular resolution images (∼0.15”) of the coronal emission in the vicinity of the central engine.To search for other articles by the author(s) go to: http://adsabs.harvard.edu/abstract_service.html

The observed infall of galaxies into the Virgo cluster puts strong constraints on the mass of the cluster. A non-parametric fully non-linear description of the infall can be made with orbit reconstructions based on Numerical Action Methods. The mass of the cluster is determined to be $1.2 \times 10^{15} M_{\odot}$. The mass-to-light ratio for the cluster is found to be seven times higher than the mean ratio found across the region within $V=3000$ km/s.To search for other articles by the author(s) go to: http://adsabs.harvard.edu/abstract_service.html

In this work I present the survey which is searching for the rise in the volume-averaged star formation rate at intermediate redshifts (z<1). This survey is a combination of the data taken with Advanced Camera for Surveys in parallel with WFPC2 (U band) of the GOODS fields. We use template fitting of the spectral energy distributions to obtain photometric redshifts and classify the objects as starbursts, early- and late-types. The colors of the starbursts were reproduced and ages were estimated with the stellar evolutionary synthesis code Starburst99. By matching the optical catalog with the Chandra X-ray catalog we have identified the X-ray sources and possible candidates for having a combination of active nuclei and starburst at intermediate redshifts. Analysis of the light concentration, asymmetry and clumpiness, shows that this sample is a mixed bag, containing dwarf ellipticals, early and late-spirals and peculiar objects which resemble mergers in progress. These results have strong implications for galaxy evolution since it shows for the first time who are the candidates for the rise of the SFR at intermediate-z.To search for other articles by the author(s) go to: http://adsabs.harvard.edu/abstract_service.html

We present long-slit HST/STIS measurements of the ionized-gas kinematics in the nucleus of three disk galaxies, namely NGC 2179, NGC 4343, NGC 4435. The sample galaxies have been selected on the basis of their ground-based spectroscopy, for displaying a strong central velocity gradient for the ionized gas, which is consistent with the presence of a circum nuclear keplerian disk (CNKD, Bertola et al. 1998; Funes et al. 2002) rotating around a super massive black hole (SMBH). For each target galaxy we obtained the Hα and [NII] 6583 Å kinematics along the major axis and two 0."25 parallel offset positions. Out of three objects only NGC 4435 turned out to have a disk of ionized gas in regular motion and a regular dust-lane morphology. Preliminary modeling indicates a SMBH mass (M[bull]) one order of magnitude lower than the one expected from the M[bull]−σc relation for galaxies (Ferrarese & Merritt 2000; Gebhardt et al. 2000).To search for other articles by the author(s) go to: http://adsabs.harvard.edu/abstract_service.html

We compare recent HST observations of Seyfert and quasar NLRs and find that type–2 AGNs follow a relation consistent with that expected for a distribution of gas ionized by a central source $R_{\rm NLR,2} \propto L^{0.32 \pm 0.05}$, while type–1 objects are fit with a steeper slope of 0.55±0.05. The latter is comparable to the scaling found for the BLR size with continuum luminosity (slope: 0.5–0.7). Therefore, we investigate what we can learn about the BLR size if the NLR size is only determined by the AGN luminosity. We find that NLR and BLR size are related linearly following $R_{\rm BLR} \propto R_{\rm NLR,1}^{0.88 \pm 0.1}$. This relation can be used to estimate BH masses.To search for other articles by the author(s) go to: http://adsabs.harvard.edu/abstract_service.html

The direct comparison of observations to numerical hydro-N-body simulations, although simple in principle, is not always trivial because of possible artificial effects produced by the instrument response and by instrumental and sky background. To overcome this problem we build the software package X-MAS (X-ray MAp Simulator) devoted to simulate X-ray observations of galaxy clusters obtained from hydro-N-body simulations.To search for other articles by the author(s) go to: http://adsabs.harvard.edu/abstract_service.html

We report the first results from a panoramic spectroscopic survey of galaxies in the rich cluster Cl0024+1654 ($z\simeq 0.4$). Using HST imaging we examine the properties of early-types as a function of cluster radius. At all cluster radii, our sample lies on a self-consistent Fundamental Plane whose zero point implies evolution since $z=0$ corresponding to $\Delta[\log (M/L_V)] = 0.14 \pm 0.06$, an overall trend consistent with previous work. Using diagnostic [O II] emission and Balmer absorption lines, we locate a population of intrinsically faint galaxies at 1–2.4 Mpc radius undergoing a period of star formation. The luminosity-dependent radial trends are suggestive of the gradual quenching of star formation for infalling galaxies. We discuss physical mechanisms that may be responsible for this environmental evolution.To search for other articles by the author(s) go to: http://adsabs.harvard.edu/abstract_service.html

$K$ band luminosity functions (LFs) of three, massive, high redshift clusters of galaxies are presented. The evolution of $K^{*}$, the characteristic magnitude of the LF, is consistent with purely passive evolution, and a redshift of formation $z_{{\rm f}} \approx 1.5-2$.To search for other articles by the author(s) go to: http://adsabs.harvard.edu/abstract_service.html

We discuss results of the mapping of both the stellar and gaseous kinematics of the nuclear region of 4 nearby Seyfert galaxies, on the basis of GMOS IFU observations in the spectral region of the CaII triplet (8500Å). We do not find in any of these galaxies central drops (within the central hundred parsecs or so) in the stellar velocity dispersions, as recently reported in the literature for a number of Seyferts. However, we do conclude that apparent drops are observed when there is contamination of the CaII triplet absorption lines by underlying line emission. When extended gas emission ([SIII]9068Å) is observed, the gas velocity field differs from the stellar velocity field. The latter is usually consistent with the classical “spider diagram” characteristic of disk galaxies.To search for other articles by the author(s) go to: http://adsabs.harvard.edu/abstract_service.html

We report the first systematic study of the supercluster-void network in the $\Lambda$CDM concordance cosmology treating voids and superclusters on an equal footing. We study the dark matter density field in real space smoothed with the $L_s = 5$ h−1Mpc Gaussian window. Superclusters and voids are defined as individual members of over-dense and under-dense excursion sets respectively. We determine the morphological properties of the cosmic web at a large number of dark matter density levels by computing Minkowski functionals for every supercluster and void. At the adopted smoothing scale individual superclusters totally occupy no more than about 5% of the total volume and contain no more than 20% of mass if the largest supercluster is excluded. Likewise, individual voids totally occupy no more than 14% of volume and contain no more than 4% of mass if the largest void is excluded. The genus of individual superclusters can be $\sim 5$ while the genus of individual voids reaches $\sim 55$, implying significant amount of substructure in superclusters and especially in voids. Large voids are typically distinctly non-spherical.To search for other articles by the author(s) go to: http://adsabs.harvard.edu/abstract_service.html

We have taken N-band spectra of the nuclear dust regions of NGC 1068 with the newly commissioned Mid-InfrareD-Interferometer (MIDI), with a spatial resolution of ∼10 milliarcsec (∼1 pc). We resolve the near-nuclear emission into a warm component (∼300 K) 2.1×3.4 pc in size and a smaller hot component. We see a strong silicate absorption in front of the central component that differs in form from normal olivine-type profiles. This thick dust structure cannot be supported for the length of the active phase of the AGN by gas pressure or turbulent motions.To search for other articles by the author(s) go to: http://adsabs.harvard.edu/abstract_service.html

We present a physical and numerical model of accretion driven growth of super-massive black holes. In this model we can account for (a) the existence of $> 10^9 \textrm{M}_\odot$ black holes already in the first quasars and (b) for the observation that the lower luminosity AGN distribution peaks later in the evolution of the Universe than that of more luminous objects.To search for other articles by the author(s) go to: http://adsabs.harvard.edu/abstract_service.html

Using two different kinds of state-of-the art numerical simulations, we discuss 1) formation of a spiral galaxy and its stellar/gaseous cores, and 2) multi-phase gas models in the circum nuclear region and their ‘pseudo-observations’ using 3-D non-LTE radiation transfer calculations for molecular lines. We found that a galactic core in a spiral galaxy seen in our N-body/SPH simulations coevolves with the galaxy itself, as a result the average mass ratio is about 0.01. The spin-axis of the core is frequently changed associating with major-mergers, where the mass accretion rate for the central 0.5 kpc is also temporally enhanced. We expect that the ‘obscuring molecular tori’ around AGNs is very inhomogeneous and turbulent on a pc-scale, and this could be resolved in the nearby active galaxies using the ALMA. We also found that the CO-to-H2 conversion factor (X-factor) calculated from 12CO (J = 1-0) is NOT uniformly distributed in the central 100 pc region, but $X_{\rm CO (J=3-2)}$ is more uniform, and ∼0.3×1020 cm−2 (K km s−1)−1 is suggested.To search for other articles by the author(s) go to: http://adsabs.harvard.edu/abstract_service.html

We present new spectroscopic observations of the 3.4μm absorption feature in a Seyfert 2 galaxy and a ULIRG. A signature of C–H bonds in aliphatic hydrocarbons, the 3.4μm feature indicates the presence of organic material in Galactic and extragalactic dust. The feature in these galaxies closely resembles that seen in the Galactic diffuse ISM and in newly-formed dust in a protoplanetary nebula. This similarity implies a common composition for the hydrocarbon component of interstellar dust in a range of galaxy types, and one which is resistant to processing in the interstellar and/or circumnuclear medium.To search for other articles by the author(s) go to: http://adsabs.harvard.edu/abstract_service.html

We present first results of numerical simulations of the dynamics of all three components of a galaxy cluster: the dark matter, the intracluster gas, and the member galaxies. Our first aim is to understand the enrichment of the gas component by studying various interaction processes between cluster galaxies and the intracluster gas, notably ram-pressure stripping and galactic winds. Our second aim is to find out how fast metals originating from such interaction processes diffuse throughtout the cluster, in order to understand observed metallicity maps of galaxy clusters obtained from X-ray observations.To search for other articles by the author(s) go to: http://adsabs.harvard.edu/abstract_service.html

We have modeled the time-variable profiles of the Hα emission line from the non-axisymmetric disk and debris tail created in the tidal disruption of a solar-type star by a $10^{6} M_{\odot}$ black hole. We find that the line profiles at these very early stages of the evolution of the post-disruption debris do not resemble the double peaked profiles expected from a rotating disk since the debris has not yet settled into such a stable structure. The predicted line profiles vary on fairly short time scales (of order hours to days). As a result of the uneven distribution of the debris and the existence of a ‘tidal tail’ (the stream of returning debris), the line profiles depend sensitively on the orientation of the tail relative to the line of sight. Given the illuminating UV/X-ray light curve, we also model the Hα light curve from the debris.To search for other articles by the author(s) go to: http://adsabs.harvard.edu/abstract_service.html

We present results of a self-consistent model of the spectral energy distribution (SED) of starburst galaxies. Two parameters control the IR SED, the mean pressure in the ISM and the destruction timescale of molecular clouds. Adding a simplified AGN spectrum provides mixing lines on IRAS color : color diagrams. This reproduces the observed colors of both AGNs and starbursts.To search for other articles by the author(s) go to: http://adsabs.harvard.edu/abstract_service.html

VLA observations of selected FR-II jets (3C208, 3C352, 3C434, 3C9 and 3C14) between 5 and 15 GHz are used to derive astrophysical properties in the jets of these radio sources. We interpret the results as giving support for unifying schemes of radio galaxies and quasars. We have also determined the Faraday rotation for jets and counter-jet sides. Rotation measures are used to constrain the internal density and mach numbers of the jets, obtaining values similar to those of quasar jets but higher than those of radio galaxies. The radio brightness can be explained by doppler boosting of the synchrotron radiation, giving evidence for orientation effects as an origin for the Laing-Garrington effect.To search for other articles by the author(s) go to: http://adsabs.harvard.edu/abstract_service.html

We present the first determination of the pairwise velocity dispersion of galaxies at different luminosity with the final release of the Two-Degree Field Galaxy Redshift Survey (2dFGRS). Our result surprisingly shows that the random velocities of the faint galaxies are very high, around $700 {\rm km\,s}^{-1}$, reaching similar values as the brightest galaxies. At intermediate luminosities slightly brighter than the characteristic luminosity $M_*$, the velocities exhibit a well defined steep minimum near $400 {\rm km\,s}^{-1}$. The result challenges the current halo model of galaxies of Yang et al. that was obtained by matching the clustering and luminosity function of 2dFGRS, and can be an important constraint in general on theories of galaxy formation, e.g., the semi-analytical model. Combining the observed luminosity dependence of clustering, our result implies that quite a fraction of faint galaxies are in massive halos of galaxy clusters as the brightest ones, but most of the $M_*$ galaxies are in galactic halos.To search for other articles by the author(s) go to: http://adsabs.harvard.edu/abstract_service.html

Using spectra of normal emission line galaxies from the First Data Release of the Sloan Digital Sky Survey (SDSS) we have investigated the relations between the extinction C(Hβ) as derived from the Hα/Hβ emission line ratio and various global parameters of the galaxies. Our main findings include: C(Hβ) is linked with the galaxy spectral type and colour, decreasing from early- to late-type spirals. It also increases with increasing metallicity and is larger for more luminous galaxies and those with older stellar populations. The extinction of the stellar light is correlated with both the extinction of the nebular light and the intrinsic galaxy colours. The optical properties of the luminous infrared galaxies in our SDSS sample are very similar to those of our entire sample of SDSS galaxies. These results have implications for the determination of global star formation rates and total stellar masses in normal galaxies.To search for other articles by the author(s) go to: http://adsabs.harvard.edu/abstract_service.html