Results 231 to 240 of about 55,785 (258)

Constraining accretion physics with gravitational waves from eccentric extreme-mass-ratio inspirals

Physical Review D
We study the evolution of eccentric, equatorial extreme-mass-ratio inspirals (EMRIs) immersed in the accretion disks of active galactic nuclei. We find that single gravitational-wave observations from these systems could provide measurements with ∼10 ...
Francisco Duque, Shubham Kejriwal, L. Sberna, L. Speri, J. Gair   +4 more
semanticscholar   +1 more source

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 ...
openaire   +1 more source

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
openaire   +1 more source

Pulsational Instability of Relativistic Accretion Disks and Its Connection to the Periodic X-Ray Time Variabilily of NGC 6814

Nippon Tenmon Gakkai obun kenkyu hokoku, 1992
The innermost region of accretion disks around relativistic compact objects is unsteady, under certain conditions. This is because inertial acoustic waves are amplified there by non-conservative effects, such as viscous stress, viscous heating and ...
F. Honma, R. Matsumoto, S. Kato
semanticscholar   +1 more source

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.
openaire   +1 more source

Accretion of gaseous disks of galaxies. II. Allowance for viscosity in a disk consisting of giant molecular clouds

Astrophysics, 1987
The evolution of the distribution of giant molecular clouds in galaxies under the influence of dynamical friction on stars and viscosity is calculated in the approximation of a collisionless gas. It is shown that in principle the joint action of the viscosity and the dynamical friction can lead to the formation of the ring-shaped distribution of giant ...
O. K. Sil'chenko, V. M. Lipunov
openaire   +1 more source

The Metallicity of Galaxy Disks: Infall versus Outflow

, 2006
Both gas accretion (infall) and winds (outflow) change a galaxy's metallicity and gas fraction, lowering the effective yield. Low effective yields in galaxies with rotation speeds
J. Dalcanton
semanticscholar   +1 more source

Water megamasers as a probe of a circumnuclear accretion disk in an active galaxy

Symposium - International Astronomical Union, 1997
In the past three years, observations of extragalactic water masers have demonstrated the extraordinary power of spectral line radio interferometry to probe the inner regions of active galaxies on subparsec scales. In the case of the active galaxy NGC 4258, the observations of Miyoshi et al.
openaire   +1 more source

Evidence for initial jet formation by an accretion disk in the radio galaxy M87

New Astronomy Reviews, 2002
Abstract The nearby E0 galaxy M87 in the Virgo Cluster contains one of the nearest examples of a powerful non-thermal jet source. In addition, HST spectroscopy of its nucleus give strong evidence for the presence of a ≈3×109 M⊙ central black hole (corresponding to Schwarzschild radius Rs∼0.0004 pc). These two facts together make M87 the best possible
J.A. Biretta, W. Junor, M. Livio
openaire   +1 more source

Collapsars as a major source of r-process elements

Nature, 2018
The production of elements by rapid neutron capture (r-process) in neutron-star mergers is expected theoretically and is supported by multimessenger observations1–3 of gravitational-wave event GW170817: this production route is in principle sufficient to
D. Siegel, J. Barnes, B. Metzger
semanticscholar   +1 more source