Related papers: Exploring Active Supermassive Black Holes at 100 M…
Recent years have seen tremendous progress in the quest to detect supermassive black holes in the centers of nearby galaxies, and gas-dynamical measurements of the central masses of active galaxies have been valuable contributions to the…
Active galaxies contain a supermassive black hole at their center, which grows by accreting matter from the surrounding galaxy. The accretion process in the central ~10 parsecs has not been directly resolved in previous observations, due to…
Radial velocity monitoring has revealed the presence of moving broad emission lines in some quasars, potentially indicating the presence of a sub-parsec binary system. Phase-referenced, near-infrared interferometric observations could map…
The supermassive black hole at the center of a distant galaxy can be weighed, in rare but realistic cases, when the galaxy acts as a strong gravitational lens. The central image that should be produced by the lens is either destroyed or…
Recent observations and stellar dynamics simulations suggest that thousand solar mass black holes can form in compact massive young star clusters. Any such clusters in the bulge of their host galaxy will spiral to the center within a few…
Infrared (IR) interferometry has made widely recognised contributions to the way we look at the dusty environment of supermassive black holes on parsec scales. It finally provided direct evidence for orientation-dependent unification of…
In recent years deep X-ray and infrared surveys have provided an efficient way to find accreting supermassive black holes, otherwise known as active galactic nuclei (AGN), in the young universe. Such surveys can, unlike optical surveys,…
Submilliarcsecond astrometry and imaging of the black hole Sgr A* at the Galactic Center may become possible in the near future at infrared and submillimetre wavelengths. This resolution is sufficient to observe the silhouette the…
This review discusses the current status of supermassive black hole research, as seen from a purely observational standpoint. Since the early '90s, rapid technological advances, most notably the launch of the Hubble Space Telescope, the…
Observations of bright and variable "reflected" X-ray emission from molecular clouds located within inner hundred parsec of our Galaxy have demonstrated that the central supermassive black hole, Sgr A*, experienced short and powerful flares…
We review the recent multifrequency studies of galactic black hole binaries, aiming at revealing the underlying emission processes and physical properties in these systems. The optical and infrared observations are important for determining…
The spectrum of the hard X-ray background records the history of accretion processes integrated over the cosmic time. Several observational and theoretical evidences indicate that a significant fraction of the energy density is obscured by…
Almost every galaxy in the local Universe is observed to have a massive black hole in the centre. The properties of these black holes are observed to tightly correlate with those of their host galaxy which has been interpreted as…
We propose the development of X-ray interferometry (XRI), to reveal the universe at high energies with ultra-high spatial resolution. With baselines which can be accommodated on a single spacecraft, XRI can reach 100 $\mu$as resolution at…
I review the status of observational determinations of central masses in nearby galactic nuclei. Results from a variety of techniques are summarized, including ground-based and space-based optical spectroscopy, radio VLBI measurements of…
Intensity interferometry is a technique developed many decades ago, that has recently enjoyed a renaissance thanks in part to advances in photodetector technology. We investigate the potential for long-baseline optical intensity…
The masses of 68 supermassive black holes (SMBHs) in nearby (z<0.15) active galactic nuclei (AGNs) detected by the INTEGRAL observatory in the hard X-ray energy band (17-60 keV) outside the Galactic plane (|b| > 5 degrees) have been…
Sub milli-arcsecond astrometry and imaging of the black hole Sgr A* at the Galactic centre may become possible in the near future at infrared and sub-millimetre wavelengths. Motivated by observations of short-term infrared and X-ray…
Supermassive black holes are a key element in our understanding of how galaxies form. Most of the progress in this very active field of research is based on just ~30 determinations of black hole mass, accumulated over the past decade. We…
Reverberation mapping is now a well-established technique for investigating spatially-unresolved structures in the nuclei of distant galaxies with actively-accreting supermassive black holes. Structural parameters for the broad…