We review recent progress on the modeling and use of reflection spectra from irradiated and ionized accretion discs. On the computational side, calculations of reflection spectra from discs with non-uniform density structure have shown that thermal instabilities can effect the predictions. Ionized reflection spectra have been used effectively in fitting data of Narrow-Line Seyfert 1 galaxies, a...

We present the results of a study of propagating warp or bending waves in accretion discs. Three dimensional hydrodynamic simulations were performed using SPH, and the results are compared with calculations based on the linear theory of warped discs. We examine the response of a gaseous disc to an initially imposed warping disturbance under a variety of physical conditions. We consider primaril...

Impacts that leave the Earth-Moon system with a large excess in angular momentum have recently been advocated as a means of generating a protolunar disc with a composition that is nearly identical to that of the Earth's mantle. We here investigate the accretion of the Moon from discs generated by such 'non-canonical' impacts, which are typically more compact than discs produced by canonical imp...

Context. Numerous studies have shown that a gap-forming Jovian mass planet embedded in protoplanetary disc, which turbulent viscosity operates, can accrete gas efficiently through the gap, and for typical parameters it doubles its ~0.1 Myr. The also migrates inwards on timescale is closely related to local viscous evolution timescale, typically 0.1 These timescales are short compared disc lifet...

Disc spectra from highly luminous black hole binaries are observed to be rather simple, despite theoretical predictions to the contrary. We collate the disc-dominated spectra from multiple observations of 10 separate sources, and show that these overwhelmingly follow a multi-temperature disc blackbody spectrum with luminosity∝ T , and that such discs are stable. These results are in conflict wi...