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Infrared, optical and ultraviolet spectropolarimetric observations have proven to be ideal tools for the study of the hidden nuclei of type-2 active galactic nuclei (AGN) and for constraining the composition and morphology of the sub-parsec…

High Energy Astrophysical Phenomena · Physics 2017-11-08 F. Marin , M. Dovciak , F. Muleri , F. F. Kislat , H. S. Krawczynski

The unified model of Seyfert galaxies suggests that there are hidden broad-line regions (HBLRs) in Seyfert 2 galaxies (S2s). However, there is increasing evidence for the appearance of a subclass of S2s lacking of HBLR (non-HBLR S2s). An…

Astrophysics · Physics 2008-11-26 E. -P Zhang , J. -M. Wang

The emission line luminosity function of active galactic nuclei (AGN) is measured from about 3000 AGN included in the main galaxy sample of the Sloan Digital Sky Survey within a redshift range of $0<z<0.15$. The $\Ha$ and [OIII]$\lambda…

We present XMM-Newton observations of four low-redshift Seyfert galaxies selected to have low host luminosities (M_g>-20 mag) and small stellar velocity dispersions (sigma_star<45 km/s), which are among the smallest stellar velocity…

Cosmology and Nongalactic Astrophysics · Physics 2014-11-20 C. E. Thornton , A. J. Barth , L. C. Ho , J. E. Greene

We examine the accretion properties in a sample of 42 hard (3-60keV) X-ray selected nearby broad-line AGNs. The energy range in the sample is harder than that usually used in the similar previous studies. These AGNs are mainly complied from…

Astrophysics · Physics 2011-02-19 J. Wang , Y. F. Mao , J. Y. Wei

We summarize recent results on the infrared (IR) nuclear properties of Seyfert galaxies. 100% of all Seyfert 1-1.9$ and ~50% of all Seyfert 2s in the CfA and RSA samples observed with HST/NICMOS show nuclear point sources at 1.6micron. We…

Astrophysics · Physics 2007-05-23 Almudena Alonso-Herrero

We use new central stellar velocity dispersions and nuclear X-ray and Halpha luminosities for the Palomar survey of nearby galaxies to investigate the distribution of nuclear bolometric luminosities and Eddington ratios for their central…

Astrophysics of Galaxies · Physics 2009-07-17 Luis C. Ho

Narrow-line Seyfert 1 AGNs (NLS1s) represent a unique stage in the black hole growth history, characterised by low black hole masses of approximately $10^{6}$-$10^{8}$ solar masses and around-Eddington accretion rates. X-ray studies of…

We present near-to-mid-infrared spectral energy distributions (SEDs) for 21 Seyfert galaxies, using subarcsecond resolution imaging data. Our aim is to compare the properties Seyfert 1 (Sy1) and Seyfert 2 (Sy2) tori using clumpy torus…

We have analyzed archival \textit{Chandra} and \textit{XMM-Newton} data for two nearly complete homogeneously selected samples of type 2 Seyfert galaxies (Sy2s). These samples were selected based on intrinsic Active Galactic Nuclei (AGN)…

Cosmology and Nongalactic Astrophysics · Physics 2015-05-20 Stephanie M. LaMassa , T. M. Heckman , A. Ptak , L. Martins , V. Wild , P. Sonnentrucker , A. Hornschemeier

We present a series of statistical tests done to a sample of 29 Seyfert 1 and 59 Seyfert 2 galaxies selected from mostly isotropic properties, their far infrared fluxes and warm infrared colors. Such selection criteria provide a profound…

(Abridged) We describe a sample of low-mass Seyfert 2 galaxies selected from the Sloan Digital Sky Survey, having a median absolute magnitude of M_g = -19.0 mag. These galaxies are Type 2 counterparts to the Seyfert 1 galaxies with…

Astrophysics · Physics 2009-11-13 A. J. Barth , J. E. Greene , L. C. Ho

In the unification scheme, narrow-lined (type 2) active galactic nuclei (AGN) are intrinsically similar to broad-lined (type 1) AGN with the exception that the line of sight to the broad emission line region and accretion disk is blocked by…

Cosmology and Nongalactic Astrophysics · Physics 2015-05-18 Yu Lu , Ting-Gui Wang , Xiao-Bo Dong , Hong-Yan Zhou

We studied the physical parameters of a sample comprising of all Spitzer/IRS public spectra of Seyfert galaxies in the mid-infrared (5.2-38$\mu$m range) under the active galactic nuclei (AGN) unified model. We compare the observed spectra…

Astrophysics of Galaxies · Physics 2016-09-29 Anelise Audibert , Rogério Riffel , Dinalva A. Sales , Miriani G. Pastoriza , Daniel Ruschel-Dutra

We build a large sample of Seyfert 2 galaxies (Sy2s) with both optical spectropolarimetric and X-ray data available, in which 29 Sy2s with the detection of polarized broad emission line (PBL) and 25 without. We find that for luminous Sy2s…

Astrophysics · Physics 2008-11-26 X. W. Shu , J. X. Wang , P. Jiang , L. L. Fan , T. G. Wang

We present and discuss the properties of a complete and well defined sample of X-ray selected type 1 AGNs including 26 Narrow-Line Seyfert 1 and 129 Broad-Line Seyfert 1 galaxies derived from the XMM-Newton Bright Serendipitous Survey…

Cosmology and Nongalactic Astrophysics · Physics 2011-05-27 A. Caccianiga , P. Severgnini , R. Della Ceca , A. Corral , R. Fanali , E. Marchese

We investigate the relation between the X-ray nuclear emission, optical emission line, radio luminosity and black hole mass for a sample of nearby Seyfert galaxies. Strong linear correlations between the 2-10 keV and [OIII], radio…

Astrophysics · Physics 2008-11-26 F. Panessa , L. Bassani , M. Cappi , M. Dadina , X. Barcons , F. J. Carrera , L. C. Ho , K. Iwasawa , S. Pellegrini

We present preliminary results of the analysis of optical spectra of two complementary samples of Seyfert galaxies. The first sample was extracted from a selection of the 4th Fermi Gamma-ray Large Area Telescope (4FGL) catalog, and consists…

Astrophysics of Galaxies · Physics 2023-11-06 Benedetta Dalla Barba , Marco Berton , Luigi Foschini , Giovanni La Mura , Amelia Vietri , Stefano Ciroi

We present nuclear spectral energy distributions (SEDs) in the range 0.4-16micron for an expanded CfA sample of Seyfert galaxies. The spectral indices from 1-16micron range from alpha_IR 0.9 to 3.8. The shapes of the spectra are correlated…

We investigate the Eddington ratio distribution of X-ray selected broad-line active galactic nuclei (AGN) in the redshift range 1.0<z<2.2, where the number density of AGNs peaks. Combining the optical and Subaru/FMOS near-infrared…

Astrophysics of Galaxies · Physics 2016-01-20 Hyewon Suh , Guenther Hasinger , Charles Steinhardt , John D. Silverman , Malte Schramm