Results 1 to 10 of about 72,258 (218)
Elusive Active Galactic Nuclei [PDF]
Monthly Notices of the Royal Astronomical Society, 2003 A fraction of active galactic nuclei do not show the classical Seyfert-type signatures in their optical spectra, i.e. they are optically "elusive". X-ray observations are an optimal tool to identify this class of objects.
A. Comastri +24 more
core +11 more sources
Proceedings of the National Academy of Sciences, 1999 Active galactic nuclei are the most powerful, long-lived objects in the Universe. Recent data confirm the theoretical idea that the power source is accretion into a massive black hole. The common occurrence of obscuration and outflows probably means that the contribution of active galactic nuclei to the power density of the Universe has been ...
Fabian AC.
europepmc +7 more sources
Obscured Active Galactic Nuclei [PDF]
AIP Conference Proceedings, 2000 The properties of the absorption in type 2, narrow line AGNs are reviewed by focusing on the X-ray indicators. I discuss the properties of the cold absorbing medium (the putative torus) and of the reprocessed components, as well as their implications for
Maiolino, R.
core +7 more sources
Fuelling Active Galactic Nuclei [PDF]
Monthly Notices of the Royal Astronomical Society: Letters, 2007 We suggest that most nearby active galactic nuclei are fed by a series of small--scale, randomly--oriented accretion events. Outside a certain radius these events promote rapid star formation, while within it they fuel the supermassive black hole.
King, A. R., Pringle, J. E.
core +6 more sources
Active Galactic Nuclei Search [PDF]
Atoms, 2017 We present the first results of medium-band photometric observations on the 1m Schmidt Telescope of Byurakan Astrophysical Observatory (Armenia). The object sample was created in the SA68 field.
Sergey Kotov, Sergey Dodonov
doaj +2 more sources
On the Unification of Active Galactic Nuclei [PDF]
The Astrophysical Journal, 2012 The inevitable spread in properties of the toroidal obscuration of active galactic nuclei (AGNs) invalidates the widespread notion that type 1 and 2 AGNs are intrinsically the same objects, drawn randomly from the distribution of torus covering factors ...
Alonso-Herrero +19 more
core +6 more sources
Flux States of Active Galactic Nuclei [PDF]
Galaxies, 2019 Blazars are known to show variability on time scales from minutes to years covering a wide range of flux states. Studying the flux distribution of a source allows for various insights.
Daniela Dorner +28 more
doaj +6 more sources
, 2010 This work represents the final year project for BSc Physics with Astrophysics degree and it mainly focuses on empirical investigation of the photometry of quasars in the Sloan Digital Sky Survey (SDSS) and the UK Infrared Telescope (UKIRT) Infrared Sky ...
Khassen, Yerbol Farkhatuly
core +2 more sources
Testing neutrino instability with active galactic nuclei [PDF]
, 1999 Active galactic nuclei and gamma ray bursts at cosmological distances are sources of high-energy electron and muon neutrinos and provide a unique test bench for neutrino instability.
P. Keränen, J. Maalampi, J. Peltoniemi
openalex +4 more sources
The Astrophysical Journal, 2023 “Changing-look active galactic nuclei” (CLAGNs) are known to change their apparent types between types 1 and 2, usually accompanied by a drastic change in their luminosity on timescales of years.
Hirofumi Noda +13 more
doaj +1 more source