The hot atmospheres of galaxies and clusters of galaxies arerepositories for the energy output from accreting, supermassive black holes located in the nuclei of galaxies. X-ray observations show that star formation fueled by gas condensing out of hot atmospheres is strongly suppressed by feedback from active galactic nuclei (AGN). This mechanism may solve ...

Powering the 1062 erg nuclear outburst in the MS0735.6+7421 cluster central galaxy by accretion with a 10% mass-to-energy conversion efficiency implies that its putative supermassive black hole (SMBH) grew by ~6 � 108 M sun over the past 100 Myr. Guided by data at several wavelengths, we place upper limits on the amount of cold gas and star formation ...

White dwarfs typically have masses in a narrow range centered at about 0.6 solar mass (M(o)). Only a few ultramassive white dwarfs (mass > 1.2 M(o)) are known. Those in binary systems are of particular interest, because a small amount of accreted mass could drive them above the Chandrasekhar limit, beyond which they become gravitationally unstable. ...

With IXO, spectroscopy of accretion onto black holes will finally rival optical and IR spectroscopy of accreting young stars. ...

A possible accretion model associated with the ionization instability of quasar disks is proposed to

We present a study of strong cool core, highly luminous (most with LX? 1045 erg s-1) clusters of galaxies in which the mean jet power of the central active galactic nucleus must be very high yet no central point X-ray source is detected. Using the unique spatial resolution of Chandra, a sample of 13 clusters is analysed, including A1835, A2204 and one of the most massive cool core clusters, ...

Material falling (accreting) onto a black hole in a binary system, or at the center of a galaxy, forms an accretion disk about the event horizon, with the inner ...

A possible accretion model associated with the ionization instability of quasar disks is proposed to

I review the X-ray observations of galactic accreting black holes and neutron stars and interpretations of these in terms of solutions of the accretion flow equations. PMID:12804240

The spectral evolution of accretion disks in X-ray binaries containing black holes is studied, based

The Evolution of Accreting Black Holes in Outburst. John A. Tomsick. Center for Astrophysics and Space Sciences, Code 0424, University of California at San ...

Properties of the neutrinos emitted during an accretion of white dwarf matter by a primordial black hole are considered. The possibility of detecting these neutrinos and their oscillations is discussed.

Binary Black Holes, Accretion Disks and Relativistic. Jets: Photocenters of Nearby AGN and Quasars. Principal Investigator: Ann E. Wehrle (Interferometry ...

We deal with phantom energy accretion onto the Schwarzschild de-Sitter black hole. The energy flux conservation, relativistic Bernoulli equation and mass flux conservation equation are formulated to discuss the phantom accretion. We discuss the conditions for critical accretion. It is found that the mass of the ...

A scenario for the central engine of AGN has been developed, consisting of a massive black hole (MBH) onto which gas accretes through an accretion disk. The accretion disk radiates the observed optical and ultraviolet continua. Surrounding the MBH is a no...

Equations are derived to describe the accretion disk in the field of a rotating black hole for an arbitrary angle between the plane of the disk and the rotation axis of the black hole. The central zone of the disk will be aligned with the equatorial plane of the black hole.

Solution for a stationary spherically symmetric accretion of the relativistic perfect fluid with an equation of state p(rho) onto the Schwarzschild black hole is presented. This solution is a generalization of Michel solution and applicable to the problem of dark energy accretion. It is shown that accretion of ...

The highest efficiency of converting rest mass into energy by accreting matter into a Kerr black hole is approximately 31% (Thorne 1974). We propose a new process in which periods of accretion from a thin disk, and the associated spin-up of the black hole, alternate with the periods of no ...

A new branch of equilibrium solutions for stationary accretion disks around black holes is found. These solutions correspond to moderately super-Eddington accretion rates. The existence of the new branch is a consequence of an additional cooling due to general relativistic Roche lobe overflow and horizontal advection of heat. On an ...

A unified theory of active galactic nuclei, based on the physics of accretion flows around massive black holes, is described. The accretion modes are dependent on the ratio of accretion rate to the mass of the hole. The spectral characteristics and radiative efficiency for the ion tori, thin disks, and radiation ...

This article reviews the physics of advection-dominated accretion flows (ADAFs) and describes applications to several black hole X-ray binaries and galactic nulcei. The possibility of using ADAFs to explore the event horizons of black holes is highlighted.

Mar 17, 2010 ... As the data show, the typical supermassive black hole, ... Usually, a supermassive black hole is surrounded by an accretion disk, ...

Supermassive black hole at the Galactic Center: Sagittarius A*. � Accretion physics .... Way's central black hole. " Not seen in other wavebands ...

The global nonlinear time-dependent evolution of the inertial-acoustic mode instability in accretion

Aug 4, 2011 ... Propagating fluctuations in the mass accretion rate of a precessing flow as a power spectral model for black hole binaries ...

Jan 31, 2005 ... KERRBB is a multi-temperature blackbody model for a thin, steady state, general relativistic accretion disk around a Kerr black hole. ...

We consider the effect of accretion of radiation in the early Universe on primordial black holes in Brans-Dicke theory. The rate of growth of a primordial black hole due to accretion of radiation in Brans-Dicke theory is considerably smaller than the rate of growth of the cosmological horizon, thus making available ...

Black holes grow by accreting matter from their surroundings. However, angular momentum provides an efficient natural barrier to accretion and so only the lowest angular momentum material will be available to feed the black holes. The standard subgrid model for black hole ...

A likely process for energy production of quasars is the release of gravitational energy from matter accretion onto a compact and massive object. One of the possible configurations is a thin accretion disk around a massive black hole (10(exp 8) to 10(exp ...

The dynamics of pair winds in the environment of the central engine of Active Galactic Nuclei (AGN) are investigated assuming super Eddington accretion onto black holes. If the accretion is assumed to be spherically symmetric with the accreting matter occ...

Too hot accretion disks in ULX and superluminal jet sources ... Standard accretion disk around Kerr black hole can explain the hard disk spectra? ...

In the classical relativistic regime, the accretion of phantom-like dark energy onto a stationary black hole reduces the mass of the black hole. We have investigated the accretion of phantom energy onto a stationary charged black hole and have determined the condition under which this ...

We study the accretion process in the region of the Preston-Poisson space-time describing a Schwarzschild black hole perturbed by an asymptotically uniform magnetic field and axisymmetric tidal structures. We find that the accretion disk shrinks and the marginally stable orbit shifts toward the black hole with the ...

Black holes pose a serious problem in cyclic or oscillating cosmology. It is speculated that, in the cyclic universe with phantom turnarounds, black holes will be torn apart by phantom energy prior to turnaround before they can create any problems. In this paper, using the mechanism of phantom accretion onto black ...

Using an accretion-disk model, accretion disk luminosities are calculated for a grid of black hole masses and accretion rates. It is shown that, as the black-hole mass increases with time, the monochromatic luminosity at a given frequency first increases and then decreases rapidly as this ...

We have constructed numerically global solutions of advective accretion disks around black holes that describe a continuous transition between the effectively optically thick outer and optically thin inner disk regions. We have concentrated on models of accretion flows with large mass accretion rates, and we have ...

Important aspects of the theory of accretion are reviewed and the theory of the spherical accretion of a polytropic gas is presented. The effect of the termination of the flow at the surface of a neutron star or white dwarf is studied with consideration given to the interaction with a magnetic field anchored to the star. Spherical ...

Black holes are most often detected by the radiation produced when they gravitationally pull in surrounding gas, in a process called accretion. The efficiency with which the hot gas radiates its thermal energy strongly influences the geometry and dynamics of the accretion flow. Both radiatively efficient thin disks and radiatively ...

Spectra of accretion disks in active galactic nuclei & X-ray binaries ... and clean probe of accretion disks and black hole physics in most generic AGN! ...

Sep 10, 2008 ... Intro/Motivation. Ray-Tracing. Disk/Corona Model. Results. Applications. X-Ray Polarization from Accreting Black Holes. Jeremy Schnittman ...

A linear theory is developed for thermal convective instability in radiating gas dominated by radiation pressure. Analysis demonstrates how the magnetic field and differential rotation will affect the onset of thermal convection in the interior of a black hole accretion disk.

The X-ray luminosity of black holes is produced through the accretion of material from their companion stars. Depending on the mass of the donor star, accretion of the material falling onto the black hole through the inner Lagrange point of the system or ...

We review the empirical constraints on accretion disk models of stellar-mass black holes based on recent multiwavelength observational results. In addition to time-averaged emission spectra, the time evolutions of the intensity and spectrum provide critic...

This paper studies the hydrodynamical problem of normal modes of small adiabatic oscillations of relativistic barotropic thin accretion disks around black holes (and compact weakly magnetic neutron stars). Employing WKB techniques, we obtain the eigen fre...

Based on previous works on black hole accretion disks, I continue to explore the disk dynamics using the finite difference method to solve the highly nonlinear problem of time-dependent alpha disk equations. Here a radially zoned model is used to develop ...

Hyper-accretion discs around black holes emit copious neutrinos and anti-neutrinos. A fraction of the emitted neutrinos convert to electron-positron plasma above the disc through the annihilation reaction $\

Active Galactic Nuclei (AGN) have very luminous centers which are so bright that the surrounding stars can not adequately account for the energy emission of AGN. One of the most accepted explanations for this energy release is black hole accretion. These ...

A possible accretion model associated with the ionization instability of quasar disks is proposed to

... universe. They are thought to be powered by the accretion of gas onto super-massive black holes at the centers of galaxies. ...

If an isolated black hole is massive enough and if it accretes matter at a fast enough rate, the outer parts of the accretion disk will become self-gravitating and may become unstable, disintegrating into fragments which could form separate stars. The fragmentation would produce around the black hole a ring of gas ...

technique called reverberation mapping. The very innermost regions of the accretion disk, within a few gravitational radii (~109 km) of the black hole ...

... the hard X-ray Galactic continuum could be the superposition of unresolved point sources such as accreting neutron stars or black holes. ...

... the hard X-ray Galactic continuum could be the superposition of unresolved point sources such as accreting neutron stars or black holes. ...

... They are generally identified from their radio emission, thought to be powered by accretion of matter onto supermassive black holes in the nuclei of ...

... They are generally identified from their radio emission, thought to be powered by accretion of matter onto supermassive black holes in the nuclei of ...

We have reviewed our recent papers on supermassive blackholes (SBH) and determined constraints in accretion theory and on the properties of black holes in AGNs. It is found that a smaller value of ? is needed in the accretion disk for Seyfert 1 galaxies than for PG quasars. This difference in the value of ? maybe lead to the different ...

Sgr A(*) is a unique, compact radio source at the Galactic center whose characteristics suggest that

of these phenomena, the one supported by the data is the following. Accreting black holes and neutron stars are observed to launch relativistic puffs of plasma:...