Results 41 to 50 of about 125,183 (220)

Galaxy Interaction and the Starburst‐Seyfert Connection [PDF]

open access: yesThe Astrophysical Journal, 2004
28 pages, to appear in The Astrophysical ...
Mouri, H., Taniguchi, Y.
openaire   +2 more sources

Optical Properties of Two Complementary Samples of Intermediate Seyfert Galaxies

open access: yesPhysics, 2023
We present first results of the analysis of optical spectra of two complementary samples of Seyfert galaxies (Seyferts). The first sample was extracted from a selection of the 4th Fermi Gamma-ray Large Area Telescope (4FGL) catalog and consists of 11 γ ...
Benedetta Dalla Barba   +5 more
doaj   +1 more source

Large-Scale Environment Properties of Narrow-Line Seyfert 1 Galaxies at z < 0.4

open access: yesFrontiers in Astronomy and Space Sciences, 2017
The large-scale environment is believed to affect the evolution and intrinsic properties of galaxies. It offers a new perspective on narrow-line Seyfert 1 galaxies (NLS1) which have not been extensively studied in this context before.
Emilia Järvelä   +5 more
doaj   +1 more source

Growth of Accreting Supermassive Black Hole Seeds and Neutrino Radiation

open access: yesJournal 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

Broad line emission from iron K- and L-shell transitions in the active galaxy 1H 0707-495

open access: yes, 2009
Since the 1995 discovery of the broad iron K-line emission from the Seyfert galaxy MCG-6-30-15 (ref. 1), broad iron K lines have been found in emission from several other Seyfert galaxies, from accreting stellar-mass black holes and even from accreting ...
T. Boller   +70 more
core   +1 more source

Microvariability in Seyfert Galaxies

open access: yesThe 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.
M. T. Carini, J. C. Noble, H. R. Miller
openaire   +1 more source

Retrograde versus Prograde Models of Accreting Black Holes

open access: yesAdvances 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
wiley   +1 more source

Forty Years of X-Raying Narrow-Line Seyfert 1 Galaxies

open access: yesActa Polytechnica CTU Proceedings, 2014
Forty years after the discovery of Narrow-Line Seyfert 1 Galaxies (NLS1s), and 20 years since the discovery of the remarkable ultrasoft soft X-ray emissions of NLS1s, strategic publications improved the understanding of the Seyfert phenomenon more ...
Thomas Boller
doaj   +1 more source

THE MID-INFRARED CONTINUA OF SEYFERT GALAXIES [PDF]

open access: yesThe Astrophysical Journal, 2009
25 pages, 3 tables, 11 figures; Accepted for Publication in Nov.
Deo, Rajesh. P.   +3 more
openaire   +2 more sources

M94 as a Unique Testbed for Black Hole Mass Estimates and AGN Activity at Low Luminosities

open access: yesAdvances 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

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