Results 21 to 30 of about 6,087 (169)
The coronal parameters of local Seyfert galaxies [PDF]
Astronomische Nachrichten, 2016 AbstractOne of the open problems for AGN is the nature of the primary X‐ray emission: It is likely due to Comptonization of soft UV photons, but the optical depth and temperature of the emitting corona were largely unknown before the launch of the Nuclear Spectroscopic Telescope Array (NuSTAR).
Marinucci, A., Tortosa, A.
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EVN observations of Seyfert galaxies [PDF]
Proceedings of The 9th European VLBI Network Symposium on The role of VLBI in the Golden Age for Radio Astronomy and EVN Users Meeting — PoS(IX EVN Symposium), 2009 In this contribution, we report on dual-frequency EVN observations of six nuclei of Seyfert galaxies imaged previously at arcsecond resolution with the VLA. These galaxies are part of a distancelimited sample of Seyferts, for which VLBI observations are available only for the brightest objects.
Francesca Panessa, Marcello Giroletti
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Star formation in southern Seyfert galaxies [PDF]
Monthly Notices of the Royal Astronomical Society, 1998 We have produced radio maps, using the Australia Telescope Compact Array, of the central regions of six southern type 2 Seyfert galaxies (NGC 1365, 4945, 6221, 6810, 7582 and Circinus) with circumnuclear star formation, to estimate the relative contribution of star formation activity compared to activity from the active galactic nucleus (AGN).
Forbes, Duncan A., Norris, R. P.
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Classifying Seyfert Galaxies with Deep Learning [PDF]
The Astrophysical Journal Supplement Series, 2021 Abstract The traditional classification for a subclass of the Seyfert galaxies is visual inspection or using a quantity defined as a flux ratio between the Balmer line and forbidden line. One algorithm of deep learning is the convolution neural network (CNN), which has shown successful classification results.
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Evolution of chemical abundances in Seyfert galaxies [PDF]
Astronomy & Astrophysics, 2007 17 pages, 15 figures, 3 tables, accepted for publication in A& ...
Francesco Calura +6 more
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Growth of Accreting Supermassive Black Hole Seeds and Neutrino Radiation
Journal of Astrophysics, Volume 2015, Issue 1, 2015., 2015 In the framework of microscopic theory of black hole (MTBH), which explores the most important processes of rearrangement of vacuum state and spontaneous breaking of gravitation gauge symmetry at huge energies, we have undertaken a large series of numerical simulations with the goal to trace an evolution of the mass assembly history of 377 plausible ...
Gagik Ter-Kazarian, Gary Wegner
wiley +1 more source
Retrograde versus Prograde Models of Accreting Black Holes
Advances in Astronomy, Volume 2013, Issue 1, 2013., 2013 There is a general consensus that magnetic fields, accretion disks, and rotating black holes are instrumental in the generation of the most powerful sources of energy in the known universe. Nonetheless, because magnetized accretion onto rotating black holes involves both the complications of nonlinear magnetohydrodynamics that currently cannot fully be
David Garofalo, Alberto J. Castro-Tirado
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Nested and Single Bars in Seyfert and Non‐Seyfert Galaxies [PDF]
The Astrophysical Journal, 2002 33 pages, including 23 postscript figures, fixed a problem with deprojected position angle profiles and the resulting bar classifications and statistics numbers and figures and tables, to appear in ...
Seppo Laine +6 more
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M94 as a Unique Testbed for Black Hole Mass Estimates and AGN Activity at Low Luminosities
Advances in Astronomy, Volume 2012, Issue 1, 2012., 2012 We discuss the peculiar nature of the nucleus of M94 (NGC 4736) in the context of new measurements of the broad Hα emission from HST‐STIS observations. We show that this component is unambiguously associated with the high‐resolution X‐ray, radio, and variable UV sources detected at the optical nucleus of this galaxy.
Anca Constantin +2 more
wiley +1 more source
Microvariability in Seyfert Galaxies
The Astronomical Journal, 2003 We present the results of a search for microvariability in a sample of eight Seyfert galaxies. Microvariability (i.e., variations occurring on timescales of tens of minutes to hours) has been conclusively demonstrated to exist in the class of active galactic nuclei (AGNs) known as blazars. Its existence in other classes of AGNs is far less certain.
H. R. Miller +3 more
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