Related papers: High Redshift Supermassive Black Holes: X-ray obse…
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…
X-rays are a critical wavelength for understanding supermassive black holes (SMBHs). X-rays probe the inner accretion flow, closest to the event horizon, where gas inspirals, releasing energy and driving black hole growth. This region also…
Black hole binaries exhibit dramatic changes in their X-ray spectral and timing properties over time, providing important clues about the physical processes that occur in these systems. Black holes and black hole candidates are prime…
X-rays are a powerful probe of the physical conditions in the nuclei of active galaxies. We review the X-ray properties of radio-quiet AGN, LINERs and ultraluminous IR galaxies based on observations carried out with the X-ray satellite…
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 fluctuating brightness of cosmic X-ray sources, particularly accreting black holes and neutron star systems, has enabled enormous progress in understanding the physics of turbulent accretion flows, the behaviour of matter on the…
The evidence for obscured AGN and in particular for obscured quasars is discussed. The spectrum and source modelling of the X-ray Background suggests that most massive black holes grow by obscured accretion. A possible major growth phase…
Over the last few years, the existence of mutual feedback effects between accreting supermassive black holes powering AGN and star formation in their host galaxies has become evident. This means that the formation and the evolution of AGN…
This dissertation elaborates on X-ray polarisation features of astrophysical environments near accreting black holes. Although the work was originally assigned to supermassive black holes in active galactic nuclei, the results are also…
I outline the theory of accretion onto black holes, and its application to observed phenomena such as X-ray binaries, active galactic nuclei, tidal disruption events, and gamma-ray bursts. The dynamics as well as radiative signatures of…
Energetic outflows appear to occur in conjunction with active mass accretion onto supermassive black holes. These outflows are most readily observed in the approximately 10% of quasars with broad absorption lines, where the observer's line…
We report the discovery of three low-mass black hole candidates residing in the centers of low-mass galaxies at z<0.3 in the Chandra Deep Field - South Survey. These black holes are initially identified as candidate active galactic nuclei…
Currently available information on fast variability of the X-ray emission from accreting collapsed objects constitutes a complex phenomenology which is difficult to interpret. We review the current observational standpoint for black-hole…
Relativistic X-ray emission lines from the inner accretion disk around black holes are reviewed. Recent observations with the Chandra X-ray Observatory, X-ray Multi-Mirror Mission-Newton, and Suzaku are revealing these lines to be good…
Spectral features can arise by reflection of coronal X-rays on a black hole accretion disc. The resulting profile bears various imprints of strong gravitational field acting on the light emitting gas. The observed shape of the reflection…
There are four major X-ray satellites currently in operation, with two more shortly to follow, and several very ambitious observatories in various stages of planning. This very rich period of X-ray observation is leading to great advances…
We briefly review some recent results from Chandra and XMM-Newton studies of the highest redshift (z > 4) active galactic nuclei (AGNs). Specific topics covered include radio-quiet quasars, radio-loud quasars, moderate-luminosity AGNs in…
Deep field observations are an essential tool to probe the cosmological evolution of galaxies. In this context, X-ray deep fields provide information about some of the most energetic cosmological objects: active galactic nuclei (AGN).…
Spectroscopy of the broad iron iron with ASCA and BeppoSAX has up opened the innermost regions of accreting black hole systems to detailed study. In this contribution, I discuss how observations with future X-ray missions will extend these…
We describe the optical, near-infrared, and radio properties of a sample of hard (2-7 keV) X-ray sources detected in a deep Chandra observation of the field surrounding the Abell 370 cluster. We combine these data with similar observations…