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We combine near-to-mid-IR Spitzer data with shorter wavelength observations (optical to X-rays) to get insights on the properties of a sample of luminous, obscured Active Galactic Nuclei (AGN). We aim at modeling their broad-band Spectral…

Cosmology and Nongalactic Astrophysics · Physics 2015-05-18 F. Pozzi , C. Vignali , A. Comastri , E. Bellocchi , J. Fritz , C. Gruppioni , M. Mignoli , R. Maiolino , L. Pozzetti , M. Brusa , F. Fiore , G. Zamorani

We present Spitzer 7-38um spectra for a 24um flux limited sample of galaxies at z~0.7 in the COSMOS field. The detailed high-quality spectra allow us to cleanly separate star formation (SF) and active galactic nucleus (AGN) in individual…

An integral part of the Unified Model for Active Galactic Nuclei (AGNs) is an axisymmetric obscuring medium, which is commonly depicted as a torus of gas and dust surrounding the central engine. However, a robust, dynamical model of the…

Cosmology and Nongalactic Astrophysics · Physics 2015-06-04 S. K. Keating , J. E. Everett , S. C. Gallagher , R. P. Deo

In order to better understand how active galactic nuclei (AGN) effect the interstellar media of their host galaxies, we perform a meta-analysis of the CO emission for a sample of $z=0.01-4$ galaxies from the literature with existing CO…

Astrophysics of Galaxies · Physics 2019-07-10 Allison Kirkpatrick , Chelsea Sharon , Erica Keller , Alexandra Pope

The XLF of AGN offers a robust tool to study the evolution and the growth of SMBHs over cosmic time. Owing to the limited area probed by X-ray surveys, optical surveys are routinely used to probe the accretion in the high redshift Universe…

We constrain the evolution of the galaxy mass and luminosity functions from the analysis of (public) multi-wavelength data in the Chandra Deep Field South (CDFS) area, obtained from the GOODS and other projects, and including very deep…

The origin of the optical flux variability in active galactic nuclei (AGN) is largely unknown. Previous studies have correlated features of the variability structure function (SF) with AGN properties, though they mostly involved…

Astrophysics of Galaxies · Physics 2026-05-06 Ashley Hai Tung Tan , Christian Wolf , Neelesh Amrutha , Christopher A. Onken , John L. Tonry , Rachel Webster

We applied image stacking on empty-field Faint Images of the Radio Sky at Twenty-Centimeters (FIRST) survey maps centred on optically identified high-redshift quasars at $z\geq4$ to uncover the hidden $\mu$Jy radio emission in these active…

Astrophysics of Galaxies · Physics 2020-07-07 Krisztina Perger , Sándor Frey , Krisztina É. Gabányi , L. Viktor Tóth

The Star formation rate (SFR) is a crucial parameter to investigate galaxy evolution. At low redshift the cosmic SFR density declines smoothly, and massive active galaxies become passive, reducing their star formation activity. This implies…

Recent studies have derived quasar luminosity functions (QLFs) at various redshifts. However, the faint side of the QLF at high redshifts is still too uncertain. An accurate estimate of the survey completeness is essential to derive an…

Changing-look active galactic nuclei (CLAGNs) are a unique population of AGNs that exhibit the appearance (turn-on) or disappearance (turn-off) of broad emission lines. This study aims to explore the intrinsic mechanisms of CLAGNs by…

Astrophysics of Galaxies · Physics 2025-11-14 Huimei Wang , Xue-Bing Wu , Nanyu Yao , Bing Lyu , Yuxuan Pang , Yuming Fu , Rui Zhu , Qian Yang

We present sub-mm photometry for 11 Hyperluminous Infrared Galaxies (HLIRGs) and use radiative transfer models for starbursts and AGN to investigate the IR emission. In all sources both a starburst and AGN are required to explain the IR…

Astrophysics · Physics 2009-11-07 D. Farrah , S. Serjeant , A. Efstathiou , M. Rowan-Robinson , A. Verma

Many Active Galactic Nuclei (AGN) surveys rely on optical emission line signatures for robust source classification. There are, however, examples of luminous AGN candidates lacking such signatures, including those from the narrow line…

We determine the 22$\mu$m luminosity evolution and luminosity function for quasars from a data set of over 20,000 objects obtained by combining flux-limited Sloan Digital Sky Survey optical and Wide field Infrared Survey Explorer…

Astrophysics of Galaxies · Physics 2016-11-09 J. Singal , J. George , A. Gerber

We present early results from the spectroscopic follow-up of a sample of candidate obscured AGN selected in the mid-infrared from the Spitzer First Look Survey. Our selection allows a direct comparison of the numbers of obscured and…

Astrophysics · Physics 2007-05-23 M. Lacy , G. Canalizo , S. Rawlings , A. Sajina , L. Storrie-Lombardi , L. Armus , F. Marleau , A. Muzzin , .

We derive the properties of dusty tori in Active Galactic Nuclei (AGN) from the comparison of observed Spectral Energy Distributions (SEDs) of SDSS quasars and a precomputed grid of torus models. The observed SEDs comprise SDSS photometry,…

We present optical spectroscopy of a sample of 77 luminous AGN and quasars selected on the basis of their mid-infrared colors. Our objects are selected from the Spitzer Extragalactic First Look Survey and SWIRE XMM-LSS fields, with a…

Astrophysics · Physics 2008-11-26 M. Lacy , A. Petric , A. Sajina , G. Canalizo , L. J. Storrie-Lombardi , L. Armus , D. Fadda , F. R. Marleau

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 present a study of the redshift evolution of the projected correlation function of 593 X-ray selected AGN with I_AB<23 and spectroscopic redshifts z<4, extracted from the 0.5-2 keV X-ray mosaic of the 2.13 deg^2 XMM-COSMOS survey. We…

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