scholarly journals Optical Spectroscopy and X-Ray Detections of a Sample of Quasars and Active Galactic Nuclei Selected in the Mid-Infrared from TwoSpitzer Space TelescopeWide-Area Surveys

2006 ◽  
Vol 133 (1) ◽  
pp. 186-205 ◽  
Author(s):  
M. Lacy ◽  
A. O. Petric ◽  
A. Sajina ◽  
G. Canalizo ◽  
L. J. Storrie-Lombardi ◽  
...  
2008 ◽  
Vol 680 (1) ◽  
pp. 130-142 ◽  
Author(s):  
Carolin N. Cardamone ◽  
C. Megan Urry ◽  
Maaike Damen ◽  
Pieter van Dokkum ◽  
Ezequiel Treister ◽  
...  

2015 ◽  
Vol 454 (1) ◽  
pp. 766-803 ◽  
Author(s):  
D. Asmus ◽  
P. Gandhi ◽  
S. F. Hönig ◽  
A. Smette ◽  
W. J. Duschl

2011 ◽  
Vol 729 (1) ◽  
pp. 22 ◽  
Author(s):  
David W. Atlee ◽  
Paul Martini ◽  
Roberto J. Assef ◽  
Daniel D. Kelson ◽  
John S. Mulchaey

2013 ◽  
Vol 9 (S304) ◽  
pp. 225-226
Author(s):  
Daniel Asmus ◽  
Sebastian F. Hönig ◽  
Poshak Gandhi ◽  
Alain Smette ◽  
Wolfgang J. Duschl

AbstractWe present the largest mid-infrared (MIR) atlas of active galactic nuclei at sub-arcsec spatial scales containing 253 objects with a median redshift of 0.016. It comprises all available ground-based high-angular resolution MIR observations performed to date with 8-meter class telescopes and includes 895 photometric measurements. All types of AGN are present in the atlas, which also includes 80 per cent of the 9-month BAT AGN sample. Therefore, this atlas and its subsamples are very well-suited for AGN unification studies. A first application of the atlas is the extension of the MIR–X-ray luminosity correlation for AGN.


2019 ◽  
Vol 484 (1) ◽  
pp. 196-203 ◽  
Author(s):  
Yoshiki Toba ◽  
Yoshihiro Ueda ◽  
Kenta Matsuoka ◽  
Megumi Shidatsu ◽  
Tohru Nagao ◽  
...  

2019 ◽  
Vol 876 (1) ◽  
pp. 50 ◽  
Author(s):  
Stephanie M. LaMassa ◽  
Antonis Georgakakis ◽  
M. Vivek ◽  
Mara Salvato ◽  
Tonima Tasnim Ananna ◽  
...  

2020 ◽  
Vol 635 ◽  
pp. L5 ◽  
Author(s):  
L. Zappacosta ◽  
E. Piconcelli ◽  
M. Giustini ◽  
G. Vietri ◽  
F. Duras ◽  
...  

Hyper-luminous quasars (Lbol ≳ 1047 erg s−1) are ideal laboratories to study the interaction and impact of the extreme radiative field and the most powerful winds in the active galactic nuclei (AGN) nuclear regions. They typically exhibit low coronal X-ray luminosity (LX) compared to the ultraviolet (UV) and mid-infrared (MIR) radiative outputs (LUV and LUV); a non-negligible fraction of them report even ∼1 dex weaker LX compared to the prediction of the well established LX–LUV and LX–LUV relations followed by the bulk of the AGN population. In our WISE/SDSS-selected Hyper-luminous (WISSH) z = 2 − 4 broad-line quasar sample, we report on the discovery of a dependence between the intrinsic 2–10 keV luminosity (L2 − 10) and the blueshifted velocity of the CIV emission line (vCIV) that is indicative of accretion disc winds. In particular, sources with the fastest winds (vCIV ≳ 3000 km s−1) possess ∼0.5–1 dex lower L2 − 10 than sources with negligible vCIV. No similar dependence is found on LUV, LUV, Lbol, the photon index, or the absorption column density. We interpret these findings in the context of accretion disc wind models. Both magnetohydrodynamic and line-driven models can qualitatively explain the reported relations as a consequence of X-ray shielding from the inner wind regions. In case of line-driven winds, the launch of fast winds is favoured by a reduced X-ray emission, and we speculate that these winds may play a role in directly limiting the coronal hard X-ray production.


2020 ◽  
Vol 499 (1) ◽  
pp. 710-729
Author(s):  
Antonis Georgakakis ◽  
Angel Ruiz ◽  
Stephanie M LaMassa

ABSTRACT An empirical forward-modelling framework is developed to interpret the multiwavelength properties of active galactic nuclei (AGNs) and provide insights into the overlap and incompleteness of samples selected at different parts of the electromagnetic spectrum. The core of the model are observationally derived probabilites on the occupation of galaxies by X-ray-selected AGN. These are used to seed mock galaxies drawn from stellar-mass functions with accretion events and then associate them with spectral energy distributions that describe both the stellar and AGN emission components. This approach is used to study the complementarity between X-ray and WISE mid-infrared AGN selection methods. We first show that the basic observational properties of the X-ray and WISE AGN (magnitude and redshift distributions) are adequately reproduced by the model. We then infer the level of contamination of the WISE selection and show that this is dominated by non-AGN at redshifts z < 0.5. These are star-forming galaxies that scatter into the WISE AGN selection wedge because of photometric uncertainties affecting their colours. Our baseline model shows a sharp drop in the number density of heavily obscured AGN above the Compton-thick limit in the WISE bands. The model also overpredicts by a factor of 1.5 the fraction of X-ray associations in the WISE AGN selection box compared to observations. This suggests a population of X-ray faint sources that is not reproduced by the model. This discrepancy is discussed in the context of either heavily obscured or intrinsically X-ray weak AGN. Evidence is found in favour of the latter.


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