Results 121 to 130 of about 23,810 (131)

The relative orientation of the accretion disk and host galaxy disk in Seyferts

New Astronomy Reviews, 2002
We present the results of the study of the orientation of the accretion disk relative to the host galaxy disk in Seyfert galaxies. We used a sample selected by a mostly isotropic property, the flux at 60 μm, with radio and optical data homogeneously observed and analyzed, to avoid selection effects.
H.R. Schmitt, A.L. Kinney
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A large nuclear accretion disk in the active galaxy NGC4261

Nature, 1993
THE powerful emissions from the nuclei of active galaxies and quasars are thought to arise from the accretion of matter onto a massive black hole. Angular momentum will prevent matter from falling directly onto the central mass; instead, an 'accretion disk' should form, within which the gravitationally bound material will lose angular momentum and ...
Walter Jaffe, Holland C. Ford, Laura Ferrarese, Frank van den Bosch, Robert W. O'Connell   +4 more
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The tilt of accretion disks in active spiral galaxies

Advances in Space Research, 1999
Abstract How are accretion disks in Seyfert Galaxies oriented relative to the disk of the spiral galaxy which hosts them? This angle, β, serves as a link between the innermost workings of the black hole plus fueling accretion disk and the larger galaxy, either as the memory of the activity-provoking event, or as a diagnostic for the structure of the ...
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Accretion Disks in the Centers of Galaxies

1988
We discuss the problems of α-accretion disks in soft potential wells of the centers of galaxies. If matter is fed into the disk only from large radii, accretion is very inefficient, as there is no shear that could drive it. If on the other hand matter falls into the disk at all radii, the disk may become so massive that it can change the potential, and
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The Effects of Satellite Accretion on Disk Galaxies

1987
Over a Hubble time, the disk of a spiral galaxy and its system of satellites can be severely altered by the action of dynamical friction. Satellites sink rapidly to the center of the disk when their orbits bring them within the optical radius. Those satellites in direct orbits with orbital planes close to that of the disk sink the fastest.
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Accretion Disks and the Link Between an AGN and its Host Galaxy

1989
We examine the possible role of accretion disks in bringing matter from the interstellar medium into the central regions of an active galactic nucleus (AGN). Thin axisymmetric accretion disks are not a viable means of transporting fuel to luminous AGNs on scales larger than a fraction of a parsec, because 1) the inflow time scale is too long; and 2 ...
Mitchell C. Begelman, Juhan Frank, Isaac Shlosman   +2 more
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A Torus-Dynamo for Magnetic Fields in Galaxies and Accretion Disks

1990
Accretion disks around compact objects as well as the gaseous components in galaxies often have the form of a torus. To study the structure and behaviour of magnetic fields generated in such rings, a kinematic αω-dynamo is investigated which is working inside a torus embedded into vacuum. Modes symmetric and antisymmetric with respect to the equatorial
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Spiral Disk Asymmetries and Other Evidence of Accretion in Nearby Galaxies

1996
Correlations between the stellar disk asymmetries measured in the K-band magnitude, B - V color, residuals from the B-band Tully-Fisher relationship, chemical abundance gradients of nearby spiral galaxies are discussed within the context of a model in which small satellites or H I clouds are accreted onto the outer disks of spiral galaxies.
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DYNAMICS OF SPIRAL GALAXIES IN NONLINEAR REGIME - NONLINEAR SOLITARY WAVES IN ACCRETION DISK

Publications of the Astronomical Observatory of Belgrade
Abstract. Theory of accretion disk is subject of several different theoretical models. Here, we list all important effects that can influence the accretion disk dynamics. For each effect, we propose nonlinear solution that is able to overcome linearly unstable structure.
Miroslava Vukčević, Edi Bon, Nataša Bon   +2 more
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Accretion Disks in Active Galaxies: The Sub‐Keplerian Paradigm^a

Annals of the New York Academy of Sciences, 1995
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