Related papers: Exploring the tilted accretion disc of AQ Men with…
In the course of its evolution, a black hole (BH) accretes gas from a wide range of directions. Given a random accretion event, the typical angular momentum of an accretion disc would be tilted by $\sim$60$^\circ$ relative to the BH spin.…
We present an analysis of CCD photometric observations of the eclipsing novalike cataclysmic variable DW UMa obtained in two different luminosity states: high and intermediate. The star presents eclipses with very different depth: ~1.2 mag…
Orientation of parsec-scale accretion disks in AGN is likely to be nearly random for different black hole feeding episodes. Since AGN accretion disks are unstable to self-gravity on parsec scales, star formation in these disks will create…
We consider the shape of an accretion disc whose outer regions are misaligned with the spin axis of a central black hole and calculate the steady state form of the warped disc in the case where the viscosity and surface densities are power…
I review recent progresses in the dynamics and the evolution of self-gravitating accretion discs. Accretion discs are a fundamental component of several astrophysical systems on very diverse scales, and can be found around supermassive…
Precessing accretion discs have long been suggested as explanations for the long periods observed in a variety of X-ray binaries, most notably Her X-1/HZ Her. We show that an instability of the disc's response to the radiation reaction…
Protostars likely accrete material at a highly time variable rate, however, measurements of accretion variability from the youngest protostars are rare, as they are still deeply embedded within their envelopes. Sub-mm/mm observations can…
We present a long-term optical and X-ray photometric study of AN UMa, one of the prototypical polar-type cataclysmic variables, tracing more than 34 years of its accretion history. Observations from both ground-based and space-based…
Measurements of the physical properties of accretion disks in active galactic nuclei are important for better understanding the growth and evolution of supermassive black holes. We present the accretion disk sizes of 22 quasars from…
We present numerical simulations of properties of a parsec-scale torus exposed to illumination by the central black hole in an active galaxy (AGN). Our physical model allows to investigate the balance between the formation of winds and…
We present the Transiting Exoplanet Surveying Satellite (TESS) light curve of the intermediate polar YY Draconis (YY Dra, also known as DO Dra). The power spectrum indicates that while there is stream-fed accretion for most of the…
The eclipse mapping method is an inversion technique that makes use of the information contained in eclipse light curves to probe the structure, the spectrum and the time evolution of accretion discs. In this review I present the basics of…
Archival data on permanent superhump systems are compiled to test the thermal stability of their accretion discs. We find that their discs are almost certainly thermally stable as expected. This result confirms Osaki's suggestion (1996)…
The idea of extra spatial dimensions arises from attempts to unify gravity with other fundamental interactions, develop a consistent theory of quantum gravity, and address open problems in particle physics and cosmology. Considerable…
We present photometric and spectroscopic observations of the low mass X-ray binary GR Mus (XB 1254-690), and find strong evidence for the presence of a negative superhump with a period that is 2.4+/-0.3% shorter than the orbital. This…
We consider the properties of the warped accretion disc in NGC 4258 which is delineated by maser emission. We use our analytical models to consider whether the disc could be warped by Lense-Thirring precession. We show that such models fit…
The innermost regions of quasars can be resolved by a gravitational-lens {\lq}telescope{\rq} on scales down to a few AU. For the purpose, X-ray observations are most preferable, because X-rays originating from the innermost regions, can be…
Microlensing observations indicate that quasar accretion discs have half-light radii larger than expected from standard theoretical predictions based on quasar fluxes or black hole masses. Blackburne and colleagues have also found a very…
A geometrically thin, optically thick, warped accretion disk with a central source of luminosity is subject to non-axisymmetric forces due to radiation pressure; the resulting torque acts to modify the warp. In a recent paper, \cite{pri96}…
Recent observations of changing-look active galactic nuclei (AGN) hint at a frequency of accretion activity not fully explained by tidal disruption events (TDEs) stemming from relaxation processes in nucleus star clusters (NSCs),…