Results 61 to 70 of about 288,656 (295)

The TANAMI Program [PDF]

, 2009
TANAMI (Tracking Active Galactic Nuclei with Austral Milliarcsecond Interferometry) is a monitoring program to study the parsec-scale structures and dynamics of relativistic jets in active galactic nuclei (AGN) of the Southern Hemisphere with the Long ...
Boeck, M., Booth, R., Dutka, M. S., Edwardsk, P., Fey, A. L., Fuhrmann, L., Hase, H., Horiuchi, S., Jauncey, D. L., Johnston, K. J., Kadler, Matthias, Katz, U., Lister, M., Lovell, J. E. J., Mueller, Cornelia, Ojha, Roopesh, Ploetz, C., Quick, J. F. H., Ros, E., Taylor, G. B., Thompson, D. J., Tingay, S. J., Tosti, G., Tzioumisk, A. K., Wilms, J., Zensus, J. A.   +25 more
core   +2 more sources

TOWARD THE STANDARD POPULATION SYNTHESIS MODEL OF THE X-RAY BACKGROUND: EVOLUTION OF X-RAY LUMINOSITY AND ABSORPTION FUNCTIONS OF ACTIVE GALACTIC NUCLEI INCLUDING COMPTON-THICK POPULATIONS [PDF]

, 2014
We present the most up to date X-ray luminosity function (XLF) and absorption function of active galactic nuclei (AGNs) over the redshift range from 0 to 5, utilizing the largest, highly complete sample ever available obtained from surveys performed with
Y. Ueda, M. Akiyama, G. Hasinger, T. Miyaji, M. Watson   +4 more
semanticscholar   +1 more source

Unwrapping the X‐ray spectra of active galactic nuclei [PDF]

Astronomische Nachrichten, 2016
AbstractActive galactic nuclei (AGN) are complex phenomena. At the heart of an AGN is a relativistic accretion disk around a spinning supermassive black hole (SMBH) with an X‐ray emitting corona and, sometimes, a relativistic jet. On larger scales, the outer accretion disk and molecular torus act as the reservoirs of gas for the continuing AGN activity.
openaire   +6 more sources

New Spectral Model for Constraining Torus Covering Factors from Broadband X-Ray Spectra of Active Galactic Nuclei [PDF]

, 2018
The basic unified model of active galactic nuclei (AGNs) invokes an anisotropic obscuring structure, usually referred to as a torus, to explain AGN obscuration as an angle-dependent effect.
M. Baloković, M. Baloković, M. Brightman, F. Harrison, A. Comastri, C. Ricci, C. Ricci, C. Ricci, J. Buchner, J. Buchner, P. Gandhi, Duncan Farrah, D. Stern   +12 more
semanticscholar   +1 more source

X-RAY LUMINOSITY FUNCTIONS OF ACTIVE GALACTIC NUCLEI [PDF]

Multiwavelength AGN Surveys, 2004
To appear in the proceedings of the conference "Multiwavelenth AGN Surveys", held in Cozumel, Mexico, December 2003 (invited talk).
openaire   +3 more sources

X-ray variability of active galactic nuclei and the flare model [PDF]

Advances in Space Research, 2006
Short-term variability of X-ray spectra has been reported for several Active Galactic Nuclei. Significant X-ray flux variations are observed within time scales down to 10^4 -- 10^5 seconds. We discuss short variability time scales in the framework of the X-ray flare model, which assumes the release of a large hard X-ray flux above a small portion of ...
M. Mouchet, Agata Różańska, Bozena Czerny, R. W. Goosmann, Michal Dovciak, Vladimir Karas, Vladimir Karas, A.-M. Dumont   +7 more
openaire   +5 more sources

The subarcsecond mid-infrared view of local active galactic nuclei – II. The mid-infrared–X-ray correlation [PDF]

, 2015
We present an updated mid-infrared (MIR) versus X-ray correlation for the local active galactic nuclei (AGN) population based on the high angular resolution 12 and 18?m continuum fluxes from the AGN subarcsecond MIR atlas and 2–10 keV and 14–195 keV data
D. Asmus, D. Asmus, D. Asmus, P. Gandhi, P. Gandhi, P. Gandhi, S. Hönig, S. Hönig, S. Hönig, A. Smette, W. Duschl, W. Duschl   +11 more
semanticscholar   +1 more source

Active Galactic Nuclei Unification and the X‐Ray Background [PDF]

The Astrophysical Journal, 2005
Active galactic nuclei (AGNs) unification, which implies a large number of obscured AGNs, can explain the optical, infrared, and X-ray content of deep multiwavelength surveys. Here we show that the same model also successfully explains the spectral shape and intensity of the X-ray background. The simplest possible unified model assumes a constant ratio
Ezequiel Treister, Ezequiel Treister, C. Megan Urry   +2 more
openaire   +3 more sources

CONSTRAINING HALO OCCUPATION PROPERTIES OF X-RAY ACTIVE GALACTIC NUCLEI USING CLUSTERING OF CHANDRA SOURCES IN THE BOÖTES SURVEY REGION

, 2010
We present one of the most precise measurements to date of the spatial clustering of X-ray-selected active galactic nuclei (AGNs) using a sample derived from the Chandra X-ray Observatory survey in the Boötes field.
S. Starikova, R. Cool, D. Eisenstein, W. Forman, C. Jones, R. Hickox, A. Kenter, C. S. Kochanek, A. Kravtsov, S. Murray, A. Vikhlinin   +10 more
semanticscholar   +1 more source

A High Fraction of Heavily X-Ray-obscured Active Galactic Nuclei

The Astrophysical Journal, 2023
We present new estimates on the fraction of heavily X-ray-obscured, Compton-thick (CT) active galactic nuclei (AGNs) out to a redshift of z ≤ 0.8. From a sample of 540 AGNs selected by mid-infrared (MIR) properties in observed X-ray survey fields, we ...
Christopher M. Carroll, Tonima T. Ananna, Ryan C. Hickox, Alberto Masini, Roberto J. Assef, Daniel Stern, Chien-Ting J. Chen, Lauranne Lanz   +7 more
doaj   +1 more source