We focus on a comparison of the space densities of FR I and FR II extended radio sources at different epochs, and find that FR I and FR II sources show similar space density enhancements in various redshift ranges, possibly implying a common evolution.

We have identified ~500 relatively relaxed galaxy clusters at low redshift (z < 0.3) from the maxBCG catalog with double radio lobes at the center; about 200 radio counterparts of brightest cluster galaxies (BCGs) of these clusters appear to be wide-angle tailed (WAT) radio sources, indicating ongoing interaction between its host galaxy and the surrounding ICM. Our analysis suggests that the radio power of WAT is positively correlated with the optical luminosities of host BCGs, and increases with redshift; whereas the cluster ellipticity-radio galaxy fraction relation shows no obvious difference between WAT and non-WAT clusters.

Polarimetry of the BL Lac object OJ 287 has been carried out over the last decade in optical bands with the 1.2-m telescope of Mt. Abu Observatory, operated by Physical Research Laboratory, India. OJ 287 underwent several polarization outbursts during this period.

We present the initial results of a multiwavelength study to detect AGN in several galaxy clusters at moderate redshifts (0.5 < z < 0.9). By using multiple epochs of HST data, we identify 10–15 optically variable galactic nuclei in each cluster. The variable and non-variable galaxies are compared with X-ray point sources.

Color selection is an efficient technique for extracting candidate AGNs. Many AGNs have been selected on the basis of colors at various wavelengths. In this work, we extracted AGN candidates using near-infrared colors and investigated their properties.

Broad absorption lines (BALs), seen in a small fraction of both the radio-quiet and radio-loud quasar populations, are probably caused by the outflow of gas with high velocities and are part of the accretion process. The presence of BALs is due to a geometrical effect and/or it is connected with the quasar evolution. Using the final release of FIRST survey combined with a catalog of BAL QSOs from SDSS/DR3, we have constructed a new sample of compact radio-loud BAL QSOs, which constitutes the majority of radio-loud BAL QSOs. The main goal of this project is to study the origin of BALs by analysis of the BAL QSOs radio morphology, orientation, and jet evolution using the European VLBI Network (EVN) at 1.6 GHz and the Very Long Baseline Array (VLBA) at 5 and 8.4 GHz.

Lagos, Padilla & Cora (2009) show that if alignments between the galaxy kinematics and the AGN system were to occur, massive galaxies should host BHs with high spin values, regardless of the detailed physics of the BH. Since the BH spin regulates the mass-to-energy conversion (Marconi et al. 2004) and possibly the existence of radio jets (Sikora et al. 2007), this study has a strong impact in our understanding of galaxy formation.

We present the first results of a Spitzer Space Telescope survey of 28 LIRGs and ULIRGs. We used infrared emission lines to separeate AGN and starburst powered systems. We find strong evidence that the incidence of nuclear activity increases with infrared luminosity.

The major challenge in studying QSO host galaxies is to remove the QSO contribution, which often outshines the whole system. Our group has acquired the technical ability to handle such data, for images and slit spectroscopy, as well as integral field spectroscopy. We review here the major techniques developed by our team, and their latest applications. We are open for collaboration with other teams to spread the use of these powerful techniques.

Supermassive black holes (SMBHs) in the centers of massive galaxies are thought to predominantly grow in brief Eddington-rate quasar phases accompanied by starbursts, but on-going starbursts in luminous quasars are difficult to observe. Buried under the natural coronagraph, obscured quasars offer a unique window for direct, robust host-galaxy spectroscopy otherwise virtually inaccessible for luminous quasars. Our pilot study at z ~ 0.5 (Liu et al. 2009) revealed a substantial contribution from very young stellar populations with ages less than ~ 100 Myr in all of the observed host galaxy spectra. More dramatically, in three out of the nine SDSS quasars observed, we have witnessed strong infant starbursts with ages of ~ 5 Myr, clocked by the telltale Wolf–Rayet emission features.

We have identified a new class of object that we term PRONGS (powerful radio objects nested in galaxies with star formation). These are powerful radio sources whose optical properties are that of spiral/star-forming galaxies, unlike classic powerful radio sources which are typically hosted by elliptical galaxies in the local Universe. Here we present a first look at these enigmatic sources.

NGC 1068 is a well-studied Seyfert type 2 AGN. Because of its proximity, it is one of the brightest Seyferts observed. Its nuclear region harbors a variety of astrophysical phenomena connected to physical conditions in the NLR and its emission lines. The relative importance of photoionization from the nucleus and shocks produced by jets has been long debated. To help resolve this controversy, we have carried out long-slit spectroscopy in the near-IR and present here for the first time spectroscopy of the whole range from 0.8 to 2.4 μm for this galaxy over 15″ in the nuclear region.

The spiral galaxy M 83, an SB(rs)b at only 4.5 Mpc, is a privileged case for study of the detailed physics on spatial scales of a tenth of a parsec. With 3-D spectroscopic observations using CIRPASS on Gemini-S, we studied the ionized gas properties in J-band with spatial resolution of 0.″5 (Figure 1). The Paβ velocity field shows two dynamical centers, neither of them coincident with the bulge center, identified with the optical nucleus (ON) and the hidden nucleus (HN), with masses, within a radius of 10 pc, of MON = (1.8±0.4)× 107M⊙ and MHN = (1.0±0.4)× 107M⊙. Using the Paβ equivalent width together with population synthesis models, we are able to estimate the ages of both mass concentrations, TON = 8 Myr and THN =6–7 Myr. Adding complexity to this puzzling scenario, we used GMOS+Gemini imaging and spectroscopy to study the radio source J133658.3–295105 (Dottori et al. 2008) and find that Hα emission at the position of this source is redshifted by ~130 km s−1 with respect to an M 83 H II region, leading us to face the possibility of that we are witnessing the ejection of an object by gravitational recoil from the M 83 nucleus. A fit to the X-ray spectrum obtained Chandra supports the association between this source and the disk of M 83 by the presence of the Fe Kα line at 6.7 keV.

We present a study of HST/STIS optical spectra of a sample of ten Seyfert galaxies aimed at analyzing the structure and physical properties of the coronal line region. The high spatial resolution provided by STIS (about 7 pc for the closest objects) allowed us to resolve the coronal line region and obtain key information about the kinematics of the coronal-line gas, measure directly its spatial scale, and study the mechanisms that drive the high-ionization lines.

In this work, we present an analysis of a data cube obtained with the instrument IFU/GMOS Gemini North telescope centered on the nuclear region of the LINER galaxy NGC 4579. This galaxy is known to have a type 1 AGN (see Eracleous et al. 2002 for a review). The methodology used for the analysis of the data cube was PCA tomography (Steiner et al. 2009), which consists of applying the statistical tool known as principal component analysis (PCA) to extract information from data cubes. The analysis was performed in the following way: first, the data cube for this object was transformed into a data matrix, where each row corresponded to a spatial pixel and each column corresponded to a spectral pixel. We then applied the PCA to this matrix, obtaining eigenvectors as a function of spectral pixels (which correspond to the original coordinates). These eigenvectors, which have the appearance of spectra, are called eigenspectra. We also calculated the projection of the data corresponding to the spatial pixels on each one of the eigenvectors. These images were called tomograms. Figure 1 shows Eigenspectrum E2 and tomogram T2 superposed on T1.

The Byurakan–IRAS galaxies (BIG objects; Mickaelian 1995) are the result of a project of optical identifications of IRAS Point Source Catalog (PSC; IRAS 1988) in a 1500 square degree high-galactic latitude (|b|>15°) area based on the Digitized Sky Survey (DSS) images and the Digitized First Byurakan Survey (DFBS, or digitized Markarian survey) low-dispersion spectra. As a result, 1278 galaxies have been identified (as well as galactic objects, Byurakan–IRAS Stars [BIS]), including 42 PSC sources identified with 103 galaxies that make up 30 physical pairs and 12 multiples.

We present a detailed investigation of the MIR continuum emission of type 1 QSOs and define the main emission components. Our model requires three components: a clumpy torus, dusty narrow-line region (NLR) clouds and a blackbody-like hot dust.

Velocity-dependent flux ratios of the broad Lyα, Civ, Hβ, and Hα lines are used to investigate conditions in the archetypical displaced BLR peak emitter 3C 390.3. Our results suggest that gas producing the the UV emission lines has a lower density than the higher-velocity gas producing broad disk-like profile and is less flattened.

We present a sample of radio galaxies selected only on the basis of radio continuum emission and we confirm that these galaxies have lower molecular gas mass than other elliptical galaxies with different selection criteria.

I present results from the Galaxy Evolution Explorer (GALEX) Key Project on “Lyman break galaxy analogs” (LBA). The LBA project was designed in order to search for nearby (z<0.3) UV-luminous starburst galaxies that could serve as a training set that can be compared with starbursts at higher redshift, in particular the population of UV-selected Lyman Break Galaxies (LBGs) at z ≳ 3 (Heckman et al. 2005; Hoopes et al. 2007). This search proved highly successful and we have since shown that there exists a rare population of nearby galaxies that is most similar to LBGs in terms of stellar mass, metallicity, extinction, star formation rate, size, morphology and gas kinematics (Overzier et al. 2008, 2009ab; Basu–Zych et al. 2007, 2009).