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We investigate the triggering mechanism and the structural properties of obscured luminous active galactic nuclei from a detailed study of the rest-frame $B$ and $I$ HST images of 29 nearby ($z\approx 0.04-0.4$) optically selected type 2…

Astrophysics of Galaxies · Physics 2019-06-05 Dongyao Zhao , Luis C. Ho , Yulin Zhao , Jinyi Shangguan , Minjin Kim

We present a statistical analysis of the properties of the obscuring material around active galactic nuclei (AGN). This study represents the first of its kind for an ultra-hard X-ray (14-195keV; Swift/BAT) volume-limited (DL<40 Mpc) sample…

We compare three different models of clumpy gas disk and show that the Circumnuclear Disk (CND) in the Galactic Center and a putative, geometrically thick, obscuring torus are best explained by a collisional model consisting of…

Astrophysics · Physics 2009-11-10 B. Vollmer , T. Beckert , W. J. Duschl

Spectra of extranuclear clouds within the ionization cone of Circinus galaxy are presented and modelled assuming photoionization by the Seyfert 2 nucleus but no preconceived assumption concerning the spectral shape of the ionizing AGN…

Astrophysics · Physics 2007-05-23 E. Oliva , A. Marconi , A. F. M. Moorwood

We present a detailed study of the highly obscured active galaxy NGC 4507, performed using four Nuclear Spectroscopic Telescope Array (NuSTAR) observations carried out between May and August in 2015 (~ 130 ks in total). Using various…

The study of neutron rich matter, present in neutron star, proto-neutron stars and core-collapse supernovae, can lead to further understanding of the behavior of nuclear matter in highly asymmetric nuclei. Heterogeneous structures are…

Nuclear Theory · Physics 2017-04-20 P. N. Alcain , C. O. Dorso

The co-evolution between black holes and galaxies suggests that feedback of active galactic nuclei influence host galaxies through ejecting radiative and kinetic energies to surroundings. Larger scale outflow in local universe are…

Astrophysics of Galaxies · Physics 2020-09-09 Zhenzhen Li , Hongyan Zhou , Lei Hao , Xiheng Shi

The excess of the rate of type I X-ray bursts over that expected when the matter fallen between bursts completely burns out in a thermonuclear explosion is explained in terms of the model of a spreading layer of matter coming from the…

High Energy Astrophysical Phenomena · Physics 2018-12-03 S. A. Grebenev , I. V. Chelovekov

We construct a new sample of 32 obscured active galactic nuclei (AGNs) selected from the Second XMM-Newton Serendipitous Source Catalogue to investigate their multiwavelength properties in relation to the "scattering fraction", the ratio of…

We describe improved modelling of the emission by dust in a toroidal--like structure heated by a central illuminating source within Active Galactic Nuclei (AGN). We chose a simple but realistic torus geometry, a flared disc, and a dust…

Astrophysics · Physics 2009-11-13 J. Fritz , A. Franceschini , E. Hatziminaoglou

High-resolution observations from the sub-mm to the optical wavelength regime resolve the central few 100pc region of nearby galaxies in great detail. They reveal a large diversity of features: thick gas and stellar discs, nuclear…

Astrophysics of Galaxies · Physics 2017-11-08 M. Schartmann , J. Mould , K. Wada , A. Burkert , M. Durré , M. Behrendt , R. I. Davies , L. Burtscher

Monte Carlo simulation is one of the best tools to study the complex spectra of Compton-thick AGNs and to figure out the relation between their nuclear structures and X-ray spectra. We have simulated X-ray spectra of Compton-thick AGNs…

Astrophysics · Physics 2009-11-13 Shinya Ikeda , Hisamitsu Awaki , Yuichi Terashima

We propose a new diagnostic of the ``dusty torus'' model for Seyfert nuclei. Dust grains in the torus are heated by the nuclear continuum, and reradiate mostly in the mid-infrared wavelengths. From the torus geometry, it is predicted that…

Astrophysics · Physics 2009-10-31 Takashi Murayama , Hideaki Mouri , Yoshiaki Taniguchi

Nuclear starburst discs (NSDs) are star-forming discs that may be residing in the nuclear regions of active galaxies at intermediate redshifts. One dimensional (1D) analytical models developed by Thompson et al. (2005) show that these discs…

High Energy Astrophysical Phenomena · Physics 2017-04-03 Raj Gohil , David R. Ballantyne

The nature of the obscuring material in active galactic nuclei is still uncertain. Although some sources, such as Cygnus A, show evidence for a geometrically thick ``torus'' as originally suggested, recent work on the radiation-driven…

Astrophysics · Physics 2007-05-23 Philip R. Maloney

We compare the arcsecond-scale circumnuclear radio continuum properties between five Seyfert and five starburst galaxies, concentrating on the search for any structures that could imply a spatial or causal connection between the nuclear…

Astrophysics · Physics 2008-11-26 Seppo Laine , Jari K. Kotilainen , Juha Reunanen , Stuart D. Ryder , Rainer Beck

Active galaxies are often associated with starbursts, which are possible sources of fuelling for the nuclear black holes. By means of optical (3500-7500 A) spectroscopic and narrow-band photometric data (H_alpha+[NII]6548,6583 and…

Astrophysics · Physics 2007-05-23 A. Romano , A. Rifatto , S. Ciroi , P. Rafanelli , M. Dopita

In Unification Models, Active Galactic Nuclei (AGN) are believed to be surrounded by an axisymmetric structure of dust and gas, which greatly influences their observed properties according to the direction from which they are observed. The…

Astrophysics · Physics 2009-11-11 E. Ibar , P. Lira

We present results from model fitting to the Spectral Energy Distribution (SED) of a homogeneous sample of Seyfert II galaxies drawn from the $12\mu$m Galaxy Sample. Imaging and nuclear flux measurements are presented in an accompanying…

Cosmology and Nongalactic Astrophysics · Physics 2015-06-12 Paulina Lira , Liza Videla , Yanling Wu , Almudena Alonso-Herrero , David M. Alexander , Martin Ward

We present preliminary results from high resolution (~ 0.05") adaptive optics observations of Cygnus A. The images show a bi-conic structure strongly suggestive of an obscuring torus around a quasar nucleus. A bright (K'=18.5) point source…

Astrophysics · Physics 2016-01-27 Gabriela Canalizo , Claire Max , Robert Antonucci , David Whysong , Alan Stockton , Mark Lacy