Results 41 to 50 of about 40,302 (261)

DYNAMICAL FRICTION AROUND SUPERMASSIVE BLACK HOLES [PDF]

open access: yesThe Astrophysical Journal, 2011
The density of stars in galactic bulges is often observed to be flat or slowly rising inside the influence radius of the supermassive black hole (SMBH). Attributing the dynamical friction force to stars moving more slowly than the test body, as is commonly done, is likely to be a poor approximation in such a core since there are no stars moving more ...
Antonini, Fabio, Merritt, David
openaire   +3 more sources

Gravitational lensing by a quantum deformed Schwarzschild black hole

open access: yesEuropean Physical Journal C: Particles and Fields, 2021
We investigate the weak and strong deflection gravitational lensing by a quantum deformed Schwarzschild black hole and find their observables. These lensing observables are evaluated and the detectability of the quantum deformation is assessed, after ...
Xu Lu, Yi Xie
doaj   +1 more source

Gravitational ringing and superradiant instabilities of the Kerr-like black holes in a dark matter halo

open access: yesEuropean Physical Journal C: Particles and Fields, 2023
Supermassive black holes from the center of galaxy may be immersed in a dark matter halo. This dark matter halo may form a “cusp” structure around the black hole and disappear at a certain distance from the black hole.
Dong Liu   +4 more
doaj   +1 more source

Black Hole Images as Tests of General Relativity: Effects of Spacetime Geometry

open access: yesThe Astrophysical Journal, 2023
The images of supermassive black holes surrounded by optically thin, radiatively inefficient accretion flows, like those observed with the Event Horizon Telescope, are characterized by a bright ring of emission surrounding the black hole shadow.
Ziri Younsi   +2 more
doaj   +1 more source

Strong deflection lensing by a Lee–Wick black hole

open access: yesPhysics Letters B, 2017
We study strong deflection gravitational lensing by a Lee–Wick black hole, which is a non-singular black hole generated by a high derivative modification of Einstein–Hilbert action.
Shan-Shan Zhao, Yi Xie
doaj   +1 more source

Black Holes, Mergers, and the Entropy Budget of the Universe

open access: yes, 2002
Vast amounts of entropy are produced in black hole formation, and the amount of entropy stored in supermassive black holes at the centers of galaxies is now much greater than the entropy free in the rest of the universe.
Abrahams A M (Binary Black Hole Grand Challenge Alliance Collaboration)   +22 more
core   +2 more sources

Spectroscopy of the near-nuclear regions of Cygnus A: estimating the mass of the supermassive black hole [PDF]

open access: yes, 2003
We use a combination of high spatial resolution optical and near-IR spectroscopic data to make a detailed study of the kinematics of the NLR gas in the near-nuclear regions of the powerful, FRII radio galaxy Cygnus A (z=0.0560), with the overall goal of ...
A. Marconi   +60 more
core   +3 more sources

A supermassive black hole awakes [PDF]

open access: yesScience, 2017
Active Galaxies Every large galaxy hosts a supermassive black hole at its center, which grows by consuming passing gas or stars. Most are quiescent, but when the black hole is feeding, an accretion disk forms, causing the galaxy nucleus to shine brightly as a quasar. Gezari et al.
openaire   +2 more sources

Tidal disruption flares from stars on eccentric orbits

open access: yesEPJ Web of Conferences, 2012
We study tidal disruption and subsequent mass fallback for stars approaching supermassive black holes on bound orbits, by performing three dimensional Smoothed Particle Hydrodynamics simulations with a pseudo-Newtonian potential.
Loeb A., Stone N., Hayasaki K.
doaj   +1 more source

Circumbinary discs from tidal disruption events

open access: yes, 2017
Tidal disruption events, which occur when a star is shredded by the tidal field of a supermassive black hole, provide a means of fueling black hole accretion. Here we show, using a combination of three body orbit integrations and hydrodynamic simulations,
Armitage, Philip J., Coughlin, Eric R.
core   +1 more source

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