Integral Field Spectroscopy provides a powerful new tool for disentangling the complex structure of Active Galactic Nuclei—allowing 2D mapping of the distribution, kinematics and excitation of ionized gas and of stellar velocity profiles and populations. Such comprehensive datasets are likely to reveal important clues about the physics of the narrow line region, interactions with the host galaxy and central dynamical forces. Here we present observations of the central regions of NGC1068, obtained using the visible-wavelength GMOS-IFU at Gemini North and NGC4151, taken with a prototype near-infrared fibre IFU at the UK Infrared Telescope.To search for other articles by the author(s) go to: http://adsabs.harvard.edu/abstract_service.html

The propagation of cosmological ionization fronts during the reionization of the universe is strongly influenced by small-scale ($\sim$ kpc) gas inhomogeneities caused by structure formation. In this paper we study this important effect by performing detailed radiative-hydrodynamic simulations of photoevaporation of cosmological minihalos (MHs) and incorporating the results into a semi-analytical model of reionization, which also includes the effect of mean intergalactic medium (IGM) clumping and the nonlinear clustering of minihalos. We find that small-scale structures have a significant effect on the process of reionization, slowing it down and extending it in time. This can help in understanding the recent observations by the Wilkinson Microwave Anisotropy Probe (WMAP) satellite, which point to an early and extended reionization epoch.To search for other articles by the author(s) go to: http://adsabs.harvard.edu/abstract_service.html

We collected X-ray and optical images for a X-ray flux-limited, complete sample of 93 active galactic nuclei (AGNs) at z<0.1, selected from the ROSAT Bright Survey. By modeling the host galaxy and the central AGN, we decompose the optical emission into nuclear, bulge and disk components. We cross-correlated our sample with the NVSS and FIRST radio catalogs, and, due to their limited sky coverage, 53 matches were found. We find that the nuclear optical luminosity, thought to be associated with the accretion disk surrounding the active black hole, correlates with the X-ray luminosity, the radio luminosity, and the black hole mass.To search for other articles by the author(s) go to: http://adsabs.harvard.edu/abstract_service.html

We discuss obbservations and numerical simulations which show that radiative shocks in jet-cloud collisions can trigger the collapse of intergalactic clouds and subsequent star formation in low luminosity, ‘FR-I’ type, radio galaxies.To search for other articles by the author(s) go to: http://adsabs.harvard.edu/abstract_service.html

We made observations of the LINER NGC 7213 in order to perform critical procedures in observing with the Eucalyptus IFU spectrograph. This object has emission lines with stellar profiles surrounded by weak extended nebular emission. We obtained narrow bands images and space resolved spectra, which suggest the existence of a bar of stellar origin.To search for other articles by the author(s) go to: http://adsabs.harvard.edu/abstract_service.html

We present a study of the emission line profiles of a sample of 12 single-peaked Active Galactic Nuclei (AGNs- Sy 1 and QSOs). The narrow [OIII] lines seem to be related to two components; NLR1, which has dispersion velocities from 200 to 500 km s−1 and is blueshifted with respect to the systemic by about 20 to 350 km s−1; and NLR2, with smaller dispersion velocities (∼100-200 km s−1) and a redshift corresponding to the cosmological one. The broad lines have complex structure and a two-component model has been applied.To search for other articles by the author(s) go to: http://adsabs.harvard.edu/abstract_service.html

We have studied the host-galaxy morphologies of narrow- and broad-line Seyfert 1 galaxies (NLS1s and BLS1s) based on broad-band optical images from the Hubble Space Telescope archives. We find that large-scale stellar bars, spanning 1–10 kpc from the nucleus, are much more common in NLS1s than BLS1s. Furthermore, the fraction of NLS1 spirals that have bars increases with decreasing full-width at half-maximum (FWHM) of the broad component of Hβ. This suggests a link between the large-scale bars, which can support high fueling rates to the inner kpc, and the high mass-accretion rates associated with the supermassive black holes in NLS1s. A preliminary examination of the inner (<1 kpc) dust morphologies has revealed no significant differences between NLS1s and BLS1s, except that we confirm the previous finding that galaxies with large-scale bars have a much higher frequency of “grand design” nuclear dust spirals.To search for other articles by the author(s) go to: http://adsabs.harvard.edu/abstract_service.html

We study the global effects of the clouds-SN shock wave interactions on the mixing of the gas in Starburst galaxies.To search for other articles by the author(s) go to: http://adsabs.harvard.edu/abstract_service.html

Results gathered to anchor the MBH−σ∗ relation raise concerns in the methods of measuring of σ∗ used for the original slope determinations. We present these preliminary results to demonstrate the problem and briefly outline where the discrepancies arise. IFS is a valuable tool in addressing this area and will allow us to remove systematics before tightening the MBH−σ∗ relation and end the “aperture arguments”.To search for other articles by the author(s) go to: http://adsabs.harvard.edu/abstract_service.html

We present a new method to decompose the stellar population mixtures in galaxies. The method combines the spectra of simple stellar populations (SSP) of different ages and metallicities, computed with the recently published high spectral resolution evolutionary synthesis models of Bruzual & Charlot (2003). Statistical mechanics techniques, based on Markov Chain Monte Carlo methods, are used in the search for the combination of SSPs which best matches an observed spectrum. The spectral base covers 10 ages and 3 metallicities. The method provides the Star Formation History (SFH) expressed in a population vector $\vec{x}$, whose components represent the fractional contribution of each SSP to the total flux (or mass). The code also estimates the velocity dispersion σ[sstarf]. A series of simulations were performed to evaluate the code's ability to recover the input parameters (SFH, extinction and velocity dispersion), to investigate the effects of noise in the data and map intrinsic degeneracies of stellar populations.To search for other articles by the author(s) go to: http://adsabs.harvard.edu/abstract_service.html

We provide an overview of a high spatial resolution study of the molecular emission (H2 and CO) in the few central arcsec region around the AGN in NGC1068. A 0.5″ resolution H2 2.12 μm line map obtained with VLT/ISAAC is presented and reveals interesting characteristics: two unequally bright knots located at 1″ (70 pc) from the nucleus, along a direction perpendicular to the ionizing cone axis. We propose a model involving differential extinction, produced in the emitting molecular disc itself, to explain the intensity difference between the two knots. This effect can arise from a simple configuration, in which the orientation of the molecular disc is slightly tilted with respect to that of the central Compton thick absorber, which blocks the X-rays along our line of sight.To search for other articles by the author(s) go to: http://adsabs.harvard.edu/abstract_service.html

Global three-dimensional (3D) magneto-hydrodynamical (MHD) simulations of accretion flow have been extensively performed recently. We calculate the emergent spectra from 3D MHD flows by the Monte Carlo radiative transfer simulations, and examine to what extent simulated MHD flows can account for the observed spectrum of Sagittarius A* (Sgr A*). It is found that the emergent spectrum from the inner part of the MHD flow (r<10rs) is consistent with the observations in the X-ray flaring state of Sgr A*, where rs is the Schwarzschild radius. However, the MHD flow can not reproduce the spectrum in the quiescent state.To search for other articles by the author(s) go to: http://adsabs.harvard.edu/abstract_service.html

Deep, high-resolution I-band images of 24 BL Lac objects between z = 0.3 and 1.3 taken with the NOT and the ESO-NTT and VLT telescopes are discussed. In 17/24 (71%) of the BL Lac objects, we detected an underlying nebulosity, in 11/17 the host of the BL Lac in the redshift range z = 0.3-1 (< z > = 0.6). The host galaxies are luminous (MI = −25.2±0.8) and large (re = 10.5±7 kpc). They are on average about 0.6 mag brighter than BL Lac host galaxies at z ∼ 0.3 indicative of evolution, whereas their half-light radii are similar. By combining our data with literature data at low-redshift and applying evolutionary models to them, we find that the properties of the host galaxies of BL Lac objects up to z ∼ 1 are compatible with passively evolving elliptical galaxies formed at a redshift of z ≥ 2. Host galaxies of low-luminosity radio-loud AGN (BL Lac/FR I) have very similar properties to the hosts of radio-quiet QSOs and high-luminosity radio-loud AGN (radio-loud QSO/FR II) over a wide redshift range. This supports the picture of the “Grand Unification”, in which AGN activity is a transient phenomenon in galaxy evolution.To search for other articles by the author(s) go to: http://adsabs.harvard.edu/abstract_service.html

We analyze long slit spectroscopy of NGC 1052, the third brightest member of a group of eleven galaxies. This elliptical is a typical LINER with a stellar rotating disk. We have found a strong negative radial gradient of the abundance ratio Mg/Fe, which suggests an enhancement of α-elements particulary towards the nuclear region, and higher metallicity and age at the galactic nucleus too. We have measured the Lick line-strength indices along the major axis of the galaxy. This information, together with single-aged stellar population models of Thomas et al. (2003), was used to determine the star formation history of NGC 1052.To search for other articles by the author(s) go to: http://adsabs.harvard.edu/abstract_service.html

We present a model for the distribution of void sizes and its evolution within the context of hierarchical scenarios of gravitational structure formation. For a proper description of the hierarchical buildup of the system of voids in the matter distribution, not only the void-in-void problem should be taken into account, but also that of the void-in-cloud issue. Within the context of the excursion set formulation of an evolving void hierarchy is one involving a two-barrier excursion problem, unlike the one-barrier problem for the dark halo evolution. This leads to voids having a peaked size distribution at any cosmic epoch, centered on a characteristic void size that evolves self-similarly in time, in distinct contrast to the distribution of virialized halo masses in not having a small-scale cut-off.To search for other articles by the author(s) go to: http://adsabs.harvard.edu/abstract_service.html

High velocity shocks may provide an important source of ionizing radiation in the NLR of active galaxies. Here we present preliminary results of a new grid of MAPPINGS III shock models for shock velocities up to 1000 km s−1. This grid significantly extends the parameter space covered by the previous models, and will serve as an important component in building multi-process models of the NLR.To search for other articles by the author(s) go to: http://adsabs.harvard.edu/abstract_service.html

The recent discovery of hidden non-axysimmetric and disk-like structures in bright Virgo dwarf elliptical and lenticular galaxies indicates that they may have late-type progenitors. Using high resolution N-body simulations we follow the evolution of disk galaxies within a $\Lambda\textrm{CDM}$ cluster simulated with $10^7$ particles where the hierarchical growth and galaxy harassment are modelled self-consistently. Most of the galaxies undergo significant morphological transformation, even at the outskirts of the cluster, and move through the Hubble sequence from disks to spheroidals. The time evolution of the simulated galaxies is compared with unsharp-masked images from the VLT and we compare the kinematics of our models with the latest high resolution spectroscopic studies from the Keck telescope. We will also discuss the properties of diffuse intra-cluster light formed by tidal debris stripped away from the infalling disks by gravitational interactions.To search for other articles by the author(s) go to: http://adsabs.harvard.edu/abstract_service.html