Results 21 to 30 of about 69 (69)
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).
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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 +7 more
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Variability and the X-ray/UV ratio of active galactic nuclei [PDF]
Astronomy and Astrophysics, 2010 16 pages, 10 figures, 1 table.
VAGNETTI, FAUSTO +3 more
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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 +2 more
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X-rays from active galactic nuclei
The Astrophysical Journal, 1981 Through detailed numerical calculations, we have shown that production of thermal photons at the self-absorbed cyclotron higher harmonics and Comptonization of those soft photons in a hot plasma with the electron temperature 10/sup 9/ K provide a natural mechanism to account for the dominant observed features of the X-ray emission in the active ...
Sachiko Tsuruta +2 more
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Review on Active-Galactic Nuclei at hard X-ray energies [PDF]
Proceedings of An INTEGRAL view of the high-energy sky (the first 10 years) - 9th INTEGRAL Workshop and celebration of the 10th anniversary of the launch — PoS(INTEGRAL 2012), 2013 Hard X-ray surveys are an important tool for the study of active galactic nuclei (AGN): they provide almost an unbiased view of absorption in the extragalactic population, allow the study of spectral features such as reflection and high energy cut-off which would otherwise be unexplored and favour the discovery of some blazars at high redshift.
R. Landi +8 more
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Radiation pressure acceleration by X-rays in active galactic nuclei [PDF]
Monthly Notices of the Royal Astronomical Society, 2001 We present calculations of the dynamics of highly ionized gas clouds that are confined by external pressure, and are ionized by AGN continuum. We focus on the gas that is seen in absorption in the X-ray spectrum of many AGN and show that such gas can reach hydrostatic equilibrium under various conditions. The principal conclusion is that the clouds can
Hagai Netzer, Doron Chelouche
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X-ray variability time scales in active galactic nuclei [PDF]
Astronomy & Astrophysics, 2009 6 pages, 1 figure, accepted for publication in Astronomy and ...
W. Ishibashi, T. J. L. Courvoisier
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Soft X-ray active galactic nuclei
The Astrophysical Journal, 1984 The discovery of 10 active galactic nuclei (AGNs) based upon optical observations of Einstein Observatory X-ray sources is reported. The new objects are optically similar to AGNs that have been identified by others with this technique. One notable exception, the quasar E1821 + 643, is associated with a previously unidentified X-ray source detected with
F. E. Marshall, S. H. Pravdo
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Ultraviolet and X-ray variability of active galactic nuclei withSwift [PDF]
Monthly Notices of the Royal Astronomical Society, 2016 14 pages, 8 figures, 4 tables in main text, plus 15 pages of figures in appendices.
D. J. K. Buisson +3 more
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