Related papers: Miscellaneous observations of active galactic nucl…

NGC 3147, NGC 4698 and 1ES 1927+654 are active galaxies that are classified as Seyfert 2s, based on the line ratios of strong narrow emission lines in their optical spectra. However, they exhibit rapid X-ray spectral variability and/or…

We present the first catalog of active galactic nuclei (AGN) detected by the LAT, corresponding to 11 months of data collected in scientific operation mode. The First LAT AGN Catalog (1LAC) includes 671 gamma-ray sources located at high…

We have used the ROSAT Bright Source Catalogue to extract a complete sample of sources selected in the band from 0.1-0.4 keV. This 1/4 keV-selected sample is comprised of 54 Seyfert galaxies, 25 BL Lacertae objects, 4 clusters and 27…

We present new spectroscopic identifications for 169 objects in the RASS-Green Bank (RGB) catalog of radio- and X-ray-emitting AGN. These data significantly increase the fraction of bright RGB objects with classifications. Specifically, we…

We present the results of the optical identifications of a set of X-ray sources from the all-sky surveys of INTEGRAL and SWIFT observatories. Optical data were obtained with Russian-Turkish 1.5-m Telescope (RTT150). Nine X-ray sources were…

We present optical spectropolarimetry of the nuclei of 36 Seyfert 1 galaxies, obtained with the William Herschel and the Anglo-Australian Telescopes from 1996 to 1999. In 20 of these, the optical emission from the active nucleus is…

We report on optical spectroscopy obtained at the 10.4m Gran Telescopio Canarias of 28 Fermi gamma-ray sources that completes the study of a sample of 60 targets of unidentified objects for which the detection of an X-ray and/or radio…

We present 180 AGN candidates based on color selection from the IRAS slow-scan deep observations, with color criteria broadened from the initial Point-Source Catalog samples to include similar objects with redshifts up to z=1 and allowing…

We report the results of a new analysis of the ROSAT Wide Field Camera (WFC) all-sky survey data, designed to detect extragalactic sources of extreme ultraviolet (EUV) radiation in regions of low Galactic N_H. We identify a total of 19…

We present the third list with results {Tables 2 to 6 are available only in electronic form at the CDS via anonymous ftp to cdsarc.u-strasbg.fr (130.79.128.5) or via http://cdsweb.u-strasbg.fr/Abstract.html. Figures A1 to A9 will be made…

We present the first INTEGRAL AGN catalog, based on observations performed from launch of the mission in October 2002 until January 2004. The catalog includes 42 AGN, of which 10 are Seyfert 1, 17 are Seyfert 2, and 9 are intermediate…

The Second Catalog of Blazars and other Active Galactic Nuclei detected by the Fermi/LAT (2LAC) includes about 1100 sources, 886 of which comprise the Clean Sample. The general properties of the different populations of sources classified…

Why are the nuclei of some galaxies more active than others? If most galaxies harbor a central massive black hole, the main difference is probably in how well it is fueled by its surroundings. We investigate the hypothesis that such a…

A fraction of active galactic nuclei do not show the classical Seyfert-type signatures in their optical spectra, i.e. they are optically "elusive". X-ray observations are an optimal tool to identify this class of objects. We combine new…

We present a study of 41 dwarf galaxies hosting active massive black holes (BHs) using Hubble Space Telescope observations. The host galaxies have stellar masses in the range of $M_\star \sim 10^{8.5}-10^{9.5}~M_\odot$ and were selected to…

We searched the Northern Hemisphere Fields of the GALEX Time-Domain Survey (TDS) for galaxies with UV variability indicative of active galactic nuclei (AGNs). We identified 48 high-probability candidate AGNs from a parent sample of 1819…

We present the fifth list with results of the Hamburg/SAO Survey for Emission-Line Galaxies (HSS therein, SAO -- Special Astrophysical Observatory, Russia). The list is a result of follow-up spectroscopy conducted with the 2.2m CAHA and 4m…

We present results based on the first INTEGRAL AGN catalogue. The catalogue includes 42 AGN, of which 10 are Seyfert 1, 17 are Seyfert 2, and 9 are intermediate Seyfert 1.5. The fraction of blazars is rather small with 5 detected objects,…

We present near and mid--IR observations of a sample of Seyfert II galaxies drawn from the $12\mu$m Galaxy Sample. The sample was observed in the J, H, K, L, M and N bands. Galaxy Surface Brightness Profiles are modeled using nuclear,…

The origin of the unification model for Active Galactic Nuclei (AGN) was the detection of broad hydrogen recombination lines in the optical polarized spectrum of the Seyfert 2 galaxy (Sy2) NGC 1068. Since then, a search for the hidden…