Related papers: Disk heating and bending instability in galaxies w…
Regions of disc galaxies with widespread star formation tend to be both gravitationally unstable and self-shielded against ionizing radiation, whereas extended outer discs with little or no star formation tend to be stable and unshielded on…
We revisit the dynamics of razor-thin, stone-cold, self-gravitating discs. By recasting the equations into standard cylindrical coordinates, the linearised vertical dynamics of an exponential disc can be followed for several gigayears on a…
The problem of how some disk galaxies avoid forming bars remains unsolved. Many galaxy models having reasonable properties continue to manifest vigorous instabilities that rapidly form strong bars and no widely-accepted idea has yet been…
We present the results of a series of numerical simulations aimed to study the evolution of a disc galaxy within the global tidal field of a group environment. Both the disc galaxy and the group are modelled as multi-component,…
Protoplanetary gas disks are likely to experience gravitational instabilites (GI's) during some phase of their evolution. Density perturbations in an unstable disk grow on a dynamic time scale into spiral arms that produce efficient outward…
We analyze the first cosmological simulations that recover the fragmentation of high-redshift galactic discs driven by cold streams. The fragmentation is recovered owing to an AMR resolution better than 70 pc with cooling below 10^4 K. We…
We use the EAGLE cosmological simulations to study the evolution of the vertical velocity dispersion of cold gas, $\sigma_{z}$, in central disc galaxies and its connection to stellar feedback, gravitational instabilities, cosmological gas…
This paper considers gravitational perturbations in geometrically thin disks with rotation curves dominated by a central object, but with substantial contributions from magnetic pressure and tension. The treatment is general, but the…
Different from Milky-Way-like galaxies, discs of gas-rich galaxies are clumpy. It is believed that the clumps form because of gravitational instability. However, a necessary condition for gravitational instability to develop is that the…
Accretion disks around black hole, neutron star, and white dwarf systems are thought to sometimes tilt, retrogradely precess, and produce hump-shaped modulations in light curves that have a period shorter than the orbital period. Although…
Planet-forming disks are fundamental objects thought to be inherited from large scale rotation, through the conservation of angular momentum during the collapse of a prestellar dense core. We investigate the possibility for a protostellar…
Spirals in galaxies have long been thought to be caused by gravitational instability in the stellar component of the disk, but discerning the precise mechanism had proved elusive. Tidal interactions, and perhaps bars, may provoke some…
Decretion (or external) disks are gas disks freely expanding to large radii due to their internal stresses. They are expected to naturally arise in tidal disruption events, around Be stars, in mass-losing post main sequence binaries, as a…
A galaxy disk embedded in a rotating halo experiences a dynamical friction force which causes it to warp when the angular momentum axes of the disk and halo are misaligned. Our fully self-consistent simulations of this process induce…
A popular model for the circumstellar disks of Be stars is that of a geometrically thin disk with a density in the equatorial plane that drops as a power law of distance from the star. It is usually assumed that the vertical structure of…
Using high resolution, two-dimensional hydrodynamical simulations, we investigate the evolution of a self-gravitating multi-phase interstellar medium in the central kiloparsec region of a galactic disk. We find that a gravitationally and…
In this contribution, I present a simplified overview of the evolution of the disk galaxy population since z=1, and a brief discussion of a few open questions. Galaxy evolution surveys have found that the disk galaxy population forms stars…
We show that spiral waves in galaxy discs churn the stars and gas in a manner that largely preserves the overall angular momentum distribution and leads to little increase in random motion. Changes in the angular momenta of individual stars…
We use recent observations of high-redshift galaxies to study the evolution of galactic disks over the redshift range 0<z<1. The data are inconsistent with models in which disks were already assembled at z=1 and have evolved only in…
Growth rates for gravitational instabilities in a thick disk of gas and stars are determined for a turbulent gas that dissipates on the local crossing time. The scale heights are derived from vertical equilibrium. The accuracy of the usual…