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The Unified Model of Active Galactic Nuclei (UMAGN) is a comprehensive theoretical framework aimed at elucidating the diverse observations of AGN, encompassing quasars and Seyfert galaxies. The Model attributes the observed variations to…

Astrophysics of Galaxies · Physics 2024-09-30 Leonardo de Lima Santos , Samuel Bueno Soltau

We evaluate the underlying assumptions for the identification of Active Galactic Nuclei (AGNs) through near- and mid-infrared photometry and spectral energy distribution (SED) fitting out to z ~ 3. For massive galaxies, log(M) > 9.5, our…

One of the remaining open issues in the context of the analysis of Active Galactic Nuclei (AGN) is the evidence that nuclear gravitational accretion is often accompanied by a concurrent starburst (SB) activity. What is, in this picture, the…

Cosmology and Nongalactic Astrophysics · Physics 2013-01-22 Anna Feltre

We report the results of the optical follow-up of a sample of $\gamma$-ray-emitting active galactic nuclei (AGN). New high-quality optical spectra were obtained using Gran Telescopio Canarias with Optical System for Imaging and low-…

We have studied the relationship between the high- and low-ionization [O IV] lambda 25.89 micron, [Ne III] lambda 15.56 micron and [Ne II] lambda 12.81 micron emission lines with the aim of constraining the active galactic nuclei (AGN) and…

The symmetry axes of active galactic nuclei (AGN) are randomly distributed in space but highly inclined sources are heavily obscured and are not seen as quasars with broad emission lines. The obscuring torus geometry determines the average…

Astrophysics of Galaxies · Physics 2021-03-10 Raj Prince , Bozena Czerny , Agnieszka Pollo

We present a sample of 18 optically-selected and X-ray detected spatially offset active galactic nuclei (AGN) from the Sloan Digital Sky Survey (SDSS). In 9 systems, the X-ray AGN is spatially offset from the galactic stellar core that is…

Astrophysics of Galaxies · Physics 2016-09-28 R. Scott Barrows , Julia M. Comerford , Jenny E. Greene , David Pooley

We use the sample of emission-line nuclei derived from a recently completed optical spectroscopic survey of nearby galaxies to quantify the incidence of local (z = 0) nuclear activity. Consistent with previous studies, we find detectable…

Astrophysics · Physics 2009-10-30 Luis C. Ho , Alexei V. Filippenko , Wallace L. W. Sargent

We use X-ray Active Galactic Nuclei (AGN) observed by the Chandra X-ray Observatory within the 9.3 deg$^2$ Bo$\rm \ddot{o}$tes field of the NDWFS to study whether there is a correlation between X-ray luminosity (L$_X$) and star formation…

Astrophysics of Galaxies · Physics 2021-10-05 G. Mountrichas , V. Buat , G. Yang , M. Boquien , D. Burgarella , L. Ciesla , K. Malek , R. Shirley

We present a new scheme for modeling the broad line region in active galactic nuclei (AGNs). It involves photoionization calculations of a large number of clouds, in several pre-determined geometries, and a comparison of the calculated line…

Astrophysics · Physics 2009-10-31 Shai Kaspi , Hagai Netzer

We present mosaicked long-slit spectral maps of 18 nearby Active Galactic Nuclei (AGNs), 2 LINERs, and 4 star-forming galaxies. With the resulting data cubes taken using the Kast dual spectrograph on the 3 m Shane telescope of the Lick…

Astrophysics of Galaxies · Physics 2018-12-21 Junjie Xia , Matthew A. Malkan , Nathaniel R. Ross , Agnes J. Ancheta

We consider the techniques to distinguish normal star forming (NSF) galaxies and active galactic nuclei (AGN) hosts using optical spectra. The observational data base is a set of 20000 galaxies extracted from the Sloan Digital Sky Survey,…

Astrophysics · Physics 2009-12-15 G. Stasinska , R. Cid Fernandes , A. Mateus , L. Sodre , N. V. Asari

We present the results of X-ray spectral analysis of 22 active galactic nuclei (AGNs) with a small scattering fraction selected from the Second XMM-Newton Serendipitous Source Catalogue using hardness ratios. They are candidates of buried…

Astrophysics of Galaxies · Physics 2014-11-20 Kazuhisa Noguchi , Yuichi Terashima , Hisamitsu Awaki

Under the unified model for active galactic nuclei (AGNs), narrow-line (Type 2) AGNs are, in fact, broad-line (Type 1) AGNs but each with a heavily obscured accretion disk. We would therefore expect the optical continuum emission from Type…

We present detailed image analysis of rest-frame optical images of 235 low-redshift ($z \leq$ 0.35) type 1 active galactic nuclei (AGNs) observed with the Hubble Space Telescope. The high-resolution images enable us to perform rigorous…

Astrophysics of Galaxies · Physics 2017-10-09 Minjin Kim , Luis C. Ho , Chien Y. Peng , Aaron J. Barth , Myungshin Im

Using the CIGALE software, we present the preliminary results of a multiwavelength analysis of eighteen low-redshift isolated galaxies with active nuclei (isolated AGNs). This sample was formed by cross-matching the 2MIG isolated AGNs…

Astrophysics of Galaxies · Physics 2025-11-26 O. Kompaniiets

The infrared is a key wavelength regime for probing the dusty, obscured nuclear regions of active galaxies. We present results from an infrared study of 87 nearby Seyfert galaxies using the Spitzer Space Telescope and ground-based…

We combine the Herschel Space Observatory PACS and SPIRE photometry with archival WISE photometry to construct the spectral energy distributions (SED) for over 300 local ($z < 0.05$), ultra-hard X-ray (14 - 195 keV) selected active galactic…

Astrophysics of Galaxies · Physics 2017-02-01 T. Taro Shimizu , Richard F. Mushotzky , Marcio Meléndez , Michael J. Koss , Amy J. Barger , Lennox L. Cowie