Related papers: Spiral waves triggered by shadows in transition di…

We examine the development of a transient spiral arm in a disk galaxy made up of both gas and stars. To this end we have performed numerical simulations in a shearing sheet (basically a rectangular patch of a disc) that contains gas in the…

Protoplanetary disks are mainly heated by radiation from the central star. Since the incident stellar flux at any radius is sensitive to the disk structure near that location, an unstable feedback may be present. Previous investigations…

Pairs of azimuthal intensity decrements at near symmetric locations have been seen in a number of protoplanetary disks. They are most commonly interpreted as the two shadows cast by a highly misaligned inner disk. Direct evidence of such an…

Gaseous substructures such as feathers and spurs dot the landscape of spiral arms in disc galaxies. One of the candidates to explain their formation is the wiggle instability of galactic spiral shocks. We study the wiggle instability using…

We examine the outer Galactic HI disk for deviations from the b=0 plane by constructing maps of disk surface density, mean height, and thickness. We find that the Galactic warp is well described by a vertical offset plus two Fourier modes…

The satellite Mimas launches a bending wave -- a warping of the rings that propagates radially through self-gravity -- at the 5:3 inner vertical resonance with Saturn's rings. We present a modification of the linear bending wave theory…

We explore the interplay between in-plane and vertical dynamics in stellar discs within the framework of the shearing box approximation. Julian and Toomre used the shearing sheet to show that leading density waves are amplified as they…

Spiral arms are observed in numerous protoplanetary discs. These spiral arms can be excited by companions, either on bound or unbound orbits. We simulate a scenario where an unbound perturber, i.e. a flyby, excites spiral arms during a…

Transition disks are protoplanetary disks with inner cavities possibly cleared by massive companions, which makes them prime targets to observe at high resolution to map their velocity structure. We present ALMA Band 6 dust and gas…

We use three dimensional simulations with coupled hydrodynamics and Monte Carlo radiative transfer to show that shadows cast by the inner disc in broken circumbinary discs move within a confined range of position angles on the outer disc.…

We propose that the two armed spiral features seen in visible Hubble Space Telescope images of scattered light in HD100546's circumstellar disk are caused by the illumination of a warped outer disk. A tilt of 6-15 degrees from the symmetry…

In order to understand the physical mechanism underlying non-steady stellar spiral arms in disk galaxies we performed a series of N-body simulations with 1.2 and 8 million particles. The initial conditions were chosen to follow…

(Abridged) We investigate the growth of spiral-arm substructure in vertically stratified, self-gravitating, galactic gas disks, using local numerical MHD simulations. Our new models extend our previous 2D studies (Kim & Ostriker 2002),…

We examine the azimuthal variations in gas-phase metallicity profiles in simulated Milky Way mass disk galaxies from the Feedback in Realistic Environments (FIRE-2) cosmological zoom-in simulation suite, which includes a sub-grid turbulent…

The origin of grand design spiral structure in galaxies is still under debate but one of promising scenarios involves tidal interactions. We use N-body simulations to study the evolution of a Milky Way-size galaxy in a Virgo-like cluster.…

Azimuthally asymmetric structures have been discovered in millimeter continuum emission from many protoplanetary disks. One hypothesis is that they are vortices produced by the Rossby wave instability, for example at edges of planet-opened…

The first mechanism invoked to explain the existence of the thick disk in the Milky Way Galaxy, were the spiral arms. Up-to-date work summon several other possibilities that together seem to better explain this component of our Galaxy. All…

We present the results of qualitative consideration of possible changes occurring during the transition from the hot accretion disc to the cool one. We argue the possible existence of one more type of spiral density waves in the inner part…

Evidence for wave-like corrugations are well established in the Milky Way and in nearby disc galaxies. These were originally detected as a displacement of the interstellar medium about the midplane, either in terms of vertical distance or…

Class II protoplanetary discs feature numerous non-axisymmetric substructures like spirals and the underlying mechanisms for their formation are still highly debated. Coincidentally, early stage, massive discs are subject to the…