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The results of spectropolarimetry surveys of obscured AGNs are reviewed, paying special attention to their implications for the existence of two populations of type 2 Seyfert galaxies -- hidden Seyfert 1s and "true" Seyfert 2s. In this…

Astrophysics · Physics 2007-05-23 Edward C. Moran

We present a broadband X-ray analysis of a new homogeneous sample of 95 active galactic nuclei (AGN) from the 22-month Swift/BAT all-sky survey. For this sample we treated jointly the X-ray spectra observed by XMM-Newton and INTEGRAL…

High Energy Astrophysical Phenomena · Physics 2015-11-20 A. A. Vasylenko , V. I. Zhdanov , E. V. Fedorova

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

Results from BeppoSAX observations of Compton--thick Seyfert 2 galaxies are summarized and reviewed, and their general properties derived and discussed. In five out of the seven observed sources, the nucleus is directly visible at high…

Astrophysics · Physics 2016-08-30 G. Matt , A. C. Fabian , M. Guainazzi , K. Iwasawa , L. Bassani , G. Malaguti

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

The discovery over the last several decades of moderate luminosity AGNs in disk-dominated galaxies - which show no "classical" bulges - suggests that secular mechanisms represent an important growth pathway for supermassive black holes in…

Deep X-ray surveys have resolved much of the X-ray background radiation below 2 keV into discrete sources, but the background above 8 keV remains largely unresolved. The obscured (type 2) Active Galactic Nuclei (AGNs) that are expected to…

Astrophysics · Physics 2008-11-26 K. C. Peterson , S. C. Gallagher , A. E. Hornschemeier , M. P. Muno , E. C. Bullard

We present modeling and interpretation of the continuum and emission lines for a sample of 51 unobscured Type 1 active galactic nuclei (AGN). All of these AGNs have high quality spectra from both XMM-Newton and Sloan Digital Sky Survey…

High Energy Astrophysical Phenomena · Physics 2015-05-30 C. Jin , M. Ward , C. Done , J. M. Gelbord

We present the combined Chandra and Swift-BAT spectral analysis of seven Seyfert 2 galaxies selected from the Swift-BAT 100-month catalog. We selected nearby (z<=0.03) sources lacking of a ROSAT counterpart and never previously observed…

High Energy Astrophysical Phenomena · Physics 2017-02-22 Stefano Marchesi , Marco Ajello , Andrea Comastri , Giancarlo Cusumano , Valentina La Parola , Alberto Segreto

This paper contains a list of new AGN candidates identified from the examination of 3500 optical spectra contained in the database of the Southern Sky Redshift Survey Extension (SSRS2). The classification of galaxies was done using standard…

Astrophysics · Physics 2007-05-23 M. A. G. Maia , J. A. Suzuki , L. N. da Costa , C. N. A. Willmer , C. Rite

The ROSAT ALL Sky Survey Bright Source Catalogue (RASS-BSC) has been correlated with the Catalogue of Principal Galaxies (PGC) to identify new extragalactic counterparts. 550 reliable optical counterparts have been detected. We took optical…

Astrophysics · Physics 2009-11-13 W. Kollatschny , R. Kotulla , W. Pietsch , K. Bischoff , M. Zetzl

We map narrow-line regions (NLRs) of 11 nearby Seyfert 2 galaxies with the optical integral-field spectrograph OASIS mounted at CFHT. We model emission-line profiles of 5 forbidden-line doublets and 2 Balmer lines, correcting for the…

Cosmology and Nongalactic Astrophysics · Physics 2015-05-13 Ivana Stoklasová , Pierre Ferruit , Eric Emsellem , Bruno Jungwiert , Emmanuel Pécontal , Sebastian F. Sánchez

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 analysed the centre of NGC 1566, which hosts a well-studied active galactic nucleus (AGN), known for its variability. With the aid of techniques such as Principal Component Analysis Tomography, analysis of the emission-line spectra,…

Astrophysics of Galaxies · Physics 2017-07-11 Patrícia da Silva , J. E. Steiner , R. B. Menezes

We present the detection of extremely broad, double-peaked, highly polarized Halpha emission lines in the nuclei of the well-known Seyfert 2 galaxies NGC 2110 and NGC 5252. These hidden broad Halpha emission lines, visible only in scattered…

Cosmology and Nongalactic Astrophysics · Physics 2010-02-23 Hien D. Tran

Type 2 AGNs with intrinsically weak broad emission lines (BELs) would be exceptions to the unified model. After examining a number of proposed candidates critically, we find that the sample is contaminated significantly by objects with BELs…

Cosmology and Nongalactic Astrophysics · Physics 2010-04-14 Yong Shi , George H. Rieke , Paul Smith , Jane Rigby , Dean Hines , Jennifer Donley , Gary Schmidt , Aleksandar M. Diamond-Stanic

We use X-ray monitoring data obtained over a broad range of time-scales to measure the broadband power spectral density functions (PSDs) of two Seyfert galaxies, the broad line Seyfert 1 NGC 3227 and the Seyfert 2 NGC 5506, which has…

Astrophysics · Physics 2007-05-23 P. Uttley , I. M. McHardy

We present ASCA X-ray results on two S0 galaxies, NGC 3065 and NGC 4203. In both galaxies, we detected hard X-ray emission from a point-like source at the nucleus. Single power law model having a photon index of 1.8 well described the…

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…

Astrophysics · Physics 2009-10-31 R. Edelson , S. Vaughan , R. Warwick , E. Puchnarewicz , I. George

NGC 3147 has been considered the best case of a true type 2 AGN: an unobscured AGN, based on the unabsorbed compact X-ray continuum, which lacks a broad line region (BLR). However, the very low luminosity of NGC 3147 implies a compact BLR,…