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We have developed an efficient Active Galactic Nucleus (AGN) selection method using 18-band Spectral Energy Distribution (SED) fitting in mid-infrared (mid-IR). AGNs are often obscured by gas and dust, and those obscured AGNs tend to be…

Astrophysics of Galaxies · Physics 2017-08-29 Ting-Chi Huang , Tomotsugu Goto , Tetsuya Hashimoto , Nagisa Oi , Hideo Matsuhara

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…

Infrared photometry and later infrared spectroscopy provided powerful diagnostics to distinguish between the main emission mechanisms in galaxies: AGN and Starburst. After the pioneering work on infrared photometry with IRAS in the far-IR…

Astrophysics of Galaxies · Physics 2009-01-23 Luigi Spinoglio , Silvia Tommasin , Matthew A. Malkan

While emission-line flux ratio diagnostics are the most common technique for identifying active galactic nuclei (AGNs) in optical spectra, applying this approach to single fiber spectra of galaxies can omit entire subpopulations of AGNs.…

Mid-infrared diagnostics are presented for a large portion of the Spitzer Infrared Nearby Galaxies Survey (SINGS) sample plus archival data from the Infrared Space Observatory and the Spitzer Space Telescope. Our main result is that these…

We investigate the emission of active galactic nuclei (AGN) dusty tori in the infrared domain. Following theoretical predictions coming from hydrodynamical simulations, we model the dusty torus as a 3D two-phase medium with high-density…

Cosmology and Nongalactic Astrophysics · Physics 2012-02-29 Marko Stalevski , Jacopo Fritz , Maarten Baes , Theodoros Nakos , Luka C. Popovic

We present mid-IR observations of the prototypical Seyfert 2 galaxy NGC 1068 obtained with ISOCAM between 5 and 16micron. The proximity of this galaxy coupled with the spectro-imaging capabilities of the instrument allow us to separate the…

Astrophysics · Physics 2007-05-23 O. Laurent , I. F. Mirabel , V. Charmandaris , E. Le Floc'h , D. Lutz , R. Genzel

We present archival Hubble Space Telescope images of the nuclear regions of 43 of the 46 Seyfert galaxies found in the volume-limited, spectroscopically-complete CfA Redshift Survey sample. Using an improved method of image contrast…

Astrophysics · Physics 2009-11-07 Richard W. Pogge , Paul Martini

We estimate the abundance of Compton-thick (CT) active galactic nuclei (AGN) based on our joint model of X-ray and infrared backgrounds. At L_{rest 2-10 keV} > 10^42 erg/s, the CT AGN density predicted by our model is a few 10^-4 Mpc^-3…

Cosmology and Nongalactic Astrophysics · Physics 2015-06-17 Yong Shi , George Helou , Lee Armus

In a matched sample of Seyfert and quiescent galaxies we simultaneously probe the stellar and molecular gas kinematics from 1 kpc down to 50 pc with the aim of identifying the dynamical processes dictating black hole accretion rates. This…

How do active galactic nuclei with low optical luminosities produce powerful radio emission? Recent studies of active galactic nuclei with moderate radio and low optical luminosities (Fanaroff & Riley class I, FR I) searching for broad…

Astrophysics of Galaxies · Physics 2021-01-19 R. C. Gleisinger , C. P. O'Dea , J. F. Gallimore , S. Wykes , S. A. Baum

Using the VLT together with the near infrared instrument ISAAC, we have obtained medium spectral and high spatial resolution observations of a sample of nearby Seyfert galaxies in the H-band. This band is particularly suited for stellar…

Astrophysics · Physics 2009-11-07 C. Boisson , S. Coupe , J. G. Cuby , M. Joly , M. J. Ward

We explore host galaxy properties and environment of a sample of Type 1 and 2 active galactic nuclei (AGN) taken from the COSMOS2015 catalog, within 0.3 $\leq z \leq$ 1.1 selected for their emission in X-rays, optical spectra and SED…

Astrophysics of Galaxies · Physics 2018-07-11 Carlos Guillermo Bornancini , Diego García Lambas

We present polarimetric maps of the Circinus galaxy nucleus in the $BVRI$ bands, obtained with VLT/FORS2. Circinus is the closest Seyfert 2 galaxy and harbours an archetypal obscured active galactic nucleus (AGN). Recent high angular…

Since many years we know that dust in the form of the dusty-molecular torus is responsible for the obscuration in active galactic nuclei (AGN) at large viewing angles and thus for the classification of AGN. Recently, we gained some…

We use hard X-ray data for an "optimal" sample of Seyfert 2 galaxies to derive the distribution of the gaseous absorbing column densities among obscured active nuclei in the local Universe. Of all Seyfert 2 galaxies in the sample, 75% are…

Astrophysics · Physics 2009-10-31 G. Risaliti , R. Maiolino , M. Salvati

I present a generalized power-law diagnostic that allows to identify the presence of active galactic nuclei (AGN) in infrared (IR) galaxies at z>1, down to flux densities at which the extragalactic IR background is mostly resolved. I derive…

Cosmology and Nongalactic Astrophysics · Physics 2015-06-15 Karina I. Caputi

We introduce a new infrared diagnostic to separate galaxies on the basis of their dominant infrared emission: stellar or nuclear. The main novelty with respect to existing diagnostics, is the usage of a broad band encompassing at the same…

Astrophysics of Galaxies · Physics 2015-06-22 Dario Fadda , Giulia Rodighiero

Narrow Line Seyfert 1 (NLS1) galaxies are remarkable for their extreme continuum and emission line properties which are not well understood. New results bearing on the spectroscopic characteristics of these objects are presented here, with…

Astrophysics · Physics 2009-11-07 Anca Constantin , Joseph C. Shields

We have performed a spectroscopic study of 7 Type 2 QSOs using the mid-infrared spectrometer IRS on board the Spitzer Space Telescope. These are (to our knowledge) the first mid-IR spectra of X-ray selected QSO2s taken. The objects have…

Astrophysics · Physics 2009-11-11 E. Sturm , G. Hasinger , I. Lehmann , V. Mainieri , R. Genzel , M. D. Lehnert , D. Lutz , L. J. Tacconi