Results 51 to 60 of about 69 (69)
X-ray emission mechanisms in active galactic nuclei
, 2016 Active Galactic Nuclei (AGN) are compact regions at the centre of active galaxies which are visible across the full electromagnetic spectrum. Their radiation comes from the accretion of matter onto a supermassive black hole. They are particularly bright in X-rays, showing several components in their spectra.
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X-Ray Spectra and Time Variability of Active Galactic Nuclei [PDF]
Annual Review of Astronomy and Astrophysics, 1984 The X-ray spectra of broad line active galactic nuclei (AGN) of all types (Seyfert I's, NELG's, broadline radio galaxies) are well fit by a power law in the .5 to 100 keV band of man energy slope alpha = .68 + or - .15. There is, as yet, no strong evidence for time variability of this slope in a given object.
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The Prospects Of X-Ray Polarimetry For Active Galactic Nuclei
, 2016 Polarimetry at optical and other wavelength continues to play an important role in our struggle to develop (super-)unification schemes for active galactic nuclei (AGN). Therefore, radio-loud and radio-quiet AGN are important targets for the future small and medium-size X-ray polarimetry missions that are currently under phase A study at NASA and ESA ...
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The X-Ray Luminosity Function of Active Galactic Nuclei
, 1999 We derive an X-ray luminosity function for active galactic nuclei (AGN) that accounts for the X-ray source counts in the 0.5-2.0 and 2-10 keV energy ranges, the redshift distribution of AGNs in the ROSAT Deep Survey (RDS), as well as the X-ray background (XRB) from 1-10 keV.
Schmidt, M. +4 more
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Active galactic nuclei and X-ray observations [PDF]
Journal of Physical Studies, 2016 A. A. Vasylenko +2 more
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The X-Ray Spectra of Active Galactic Nuclei
Physica Scripta, 1984Recent observations of the X-ray spectra of active galactic nuclei are reviewed. After an outline of the properties of these sources deduced from observations at other wavelengths, the relevance of X-ray spectra to our understanding of the X-ray emission mechanisms and of the ultimate source of energy is discussed.
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X-rays from active galactic nuclei ? Hard component
Space Science Reviews, 1981It is now well known that X-ray emission in active galactic nuclei (AGN) is a fairly common phenomenon (see M.J. Rees’s review in this volume). By examining the recent observational information from Ariel V, HEAO-1, and the Einstein Observatory, we have reached the conclusion (Tsuruta 1981) that the following interpretation may be used as a relevant ...
S. Ichimaru +2 more
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Limits of X-ray variability in active galactic nuclei
Nature, 1986A significant correlation is demonstrataed here between the X-ray luminosity and the timescale of X-ray variability for Seyfert galaxies and quasars. This is interpreted as evidence that the emitting plasma is near the limit of being dominated by electron-positron pairs.
R. F. Mushotzky, P. Barr
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The X-ray variability of active galactic nuclei
2008Recent results relating to the X-ray variability exhibited by active galactic nuclei are reviewed. EXOSAT observations have established, contrary to earlier indications, that X-ray variability on a timescale of an hour or less is a relatively common feature of such sources.
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