Results 21 to 30 of about 6,096 (167)
Unabsorbed Seyfert 2 galaxies [PDF]
Astronomy & Astrophysics, 2002 We present a sample of 17 type 2 Seyfert galaxies which have an X-ray column density lower than 10^{22} cm^{-2}. The Compton thin nature of these sources is strongly suggested by isotropic indicators. We estimate the fraction of these sources to be in the range of 10% - 30% of the population of type 2 Seyfert galaxies.
Panessa F., Bassani L.
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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
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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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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
Host galaxies of jetted narrow-line Seyfert 1 galaxies [PDF]
Proceedings of Revisiting narrow-line Seyfert 1 galaxies and their place in the Universe — PoS(NLS1-2018), 2018 We performed $J$-band observations of the host galaxies of nine narrow-line Seyfert 1 galaxies (NLS1). Seven of these sources have been detected at 37 GHz and are likely to host relativistic jets. Host galaxy properties of the jetted NLS1 galaxies are not yet well known, and investigating them is essential to get more insight into their characteristics
Lähteenmäki, Anne +3 more
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The Astronomical Journal, 1982 As part of an ongoing program of measuring galaxy redshifts at Mount Hopkins observatory, we have discovered several previously unknown bright Seyfert galaxies. Most of the objects are of Seyfert type 2, but several are type 1 objects where the broad permitted line region is easily visible only for the H..cap alpha.. line.
J. P. Huchra, W. F. Wyatt, M. Davis
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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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Recoiling Black Holes: Electromagnetic Signatures, Candidates, and Astrophysical Implications
Advances in Astronomy, Volume 2012, Issue 1, 2012., 2012 Supermassive black holes (SMBHs) may not always reside right at the centers of their host galaxies. This is a prediction of numerical relativity simulations, which imply that the newly formed single SMBH, after binary coalescence in a galaxy merger, can receive kick velocities up to several 1000 km/s due to anisotropic emission of gravitational waves ...
S. Komossa, Francesca Civano
wiley +1 more source
Probing extreme black‐hole outflows on short timescales via high spectral‐resolution x‐ray imagers
Astronomische Nachrichten, Volume 345, Issue 6-7, July-August 2024.Abstract We investigate outflows and the physics of super‐Eddington versus sub‐Eddington regimes in black hole systems. Our focus is on prospective science using next‐generation high‐resolution soft x‐ray instruments. We highlight the properties of black hole ultraluminous x‐ray source (ULX) systems in particular. Owing to scale invariance in accreting
C. Pinto +9 more
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The Cosmic History of Black Hole Growth from Deep Multiwavelength Surveys
Advances in Astronomy, Volume 2012, Issue 1, 2012., 2012 Significant progress has been made in the last few years on understanding how supermassive black holes form and grow. In this paper, we begin by reviewing the spectral signatures of active galactic nuclei (AGN) ranging from radio to hard X‐ray wavelengths.
Ezequiel Treister +2 more
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