Related papers: An X-ray emitting black hole in a globular cluster

We address a question whether the observed light curves of X-ray flares originating deep in galactic cores can give us independent constraints on the mass of the central supermassive black hole. To this end we study four brightest flares…

This paper reviews the X-ray, optical, radio and IR observations of galactic X-ray binaries suspected to contain black hole compact objects, with particular emphasis on the supporting dynamical evidence.

Roughly a dozen X-ray binaries are presently known in which the compact accreting primary stars are too massive to be neutron stars. These primaries are identified as black holes, though there is as yet no definite proof that any of the…

Accreting binaries containing a black hole are stellar systems composed of a normal star and a black hole. Because of the strong gravitational pull of the black hole, matter is removed from the companion star and falls into the compact ob…

The ultraviolet/optical continuum of quasars is thought to be from an accretion flow around a supermassive black hole, and it dominates the radiative output of quasars. However, the nature of this emission, often called the Big Blue Bump,…

Iron line emission is common in the X-ray spectra of accreting black holes. When the line emission is broad or variable then it is likely to originate from close to the black hole. X-ray irradiation of the accretion flow by the power-law…

There is strong evidence for the existence of black holes(BHs) in some X-ray binaries and most galatic nuclei, based on different measuremental approaches, but black holes aren't finally identified for the lack of very firm observational…

Accretion onto supermassive black holes powers the most luminous persistent sources in the Universe, the so-called active galactic nuclei, whose emission is characterized by two distinct spectral components: thermal optical/ultraviolet…

The most compelling evidences for the existence of stellar-mass black holes have been obtained through observations of X-ray binary systems. The application of classical methods and the development of new techniques have allowed us to…

X-ray studies of high-redshift (z > 4) active galaxies have advanced substantially over the past few years, largely due to results from the new generation of X-ray observatories. As of this writing X-ray emission has been detected from…

The X-ray spectra of accreting stellar-mass black hole systems exhibit spectral features due to reflection, especially broad iron K alpha emission lines. We investigate the reflection by the accretion disc that can be expected in the…

We present a simple argument that the missing x-ray flux from the Galactic Center source Sgr~A* ist not evidence {\it against} -- as claimed by Goldwurm et al. 1994 -- but rather indirect evidence {\it for} the presence of a supermassive…

We present a multi-facility study of the optical spectrum of the extragalactic globular cluster RZ2109, which hosts a bright black hole X-ray source. The optical spectrum of RZ2109 shows strong and very broad [O III]\lambda \lambda…

In X-ray binary star systems consisting of a compact object that accretes material from an orbiting secondary star, there is no straightforward means to decide if the compact object is a black hole or a neutron star. To assist this…

X-ray reflection spectra are an important component in the X-ray spectra of many active galactic nuclei and Galactic black hole candidates. It is likely that reflection takes place from highly ionized surfaces of the accretion disc in some…

The high energy radiation emitted by black hole X-ray binaries originates in an accretion disk, hence the variability of the lightcurves mirrors the dynamics of the disc. We study the time evolution of the emitted flux in order to find…

Hundreds of stellar-mass black holes likely form in a typical globular star cluster, with all but one predicted to be ejected through dynamical interactions. Some observational support for this idea is provided by the lack of X-ray-emitting…

Accretion onto black holes is one of the most efficient energy source in the Universe. Black hole accretion powers some of the most luminous objects in the universe, including quasars, active galactic nuclei, tidal disruption events,…

We report results obtained from six XMM-Newton observations of the Seyfert galaxy 1H 0419-577. Here we show that the X-ray spectrum and variability are well described by a two-component model comprising a power law with constant spectral…

NGC 4472 is home to five ultraluminous X-ray sources hosted by globular clusters. These sources have been suggested as good black hole candidates in extragalactic globular clusters$-$ a highly sought after population that may provide…