相关论文: On the stability of a galactic disk in modified gr…

We propose that turbulent heating, wave pressure and gas exchanges between different regions of disks play a dominant role in determining the preferred, quasi-equilibrium, self-similar states of gas disks on large-scales. We present simple…

A typical galactic disc has a finite thickness and in addition to stars it also contains a finite amount of interstellar gas. Here, we investigate the physical impact of the finite thickness of a galactic disc on the disc stability against…

In this paper we examine the issue of characterising the transport associated with gravitational instabilities in relatively cold discs, discussing in particular the conditions under which it can be described within a local, viscous…

This paper constructs a theoretical framework for calculating the distribution of masses for secondary bodies forming via gravitational instability in the outer regions of circumstellar disks. We show that several alternate ways to specify…

Gas disks of spiral galaxies can be described as clumpy accretion disks without a coupling of viscosity to the actual thermal state of the gas. The model description of a turbulent disk consisting of emerging and spreading clumps (Vollmer &…

We use smoothed particle hydrodynamics simulations of massive protostellar discs to investigate the predicted broadening of molecular lines from discs in which self-gravity is the dominant source of angular momentum transport. The…

Star formation laws, like i.e. the Schmidt law relating star formation rate and total gas density, have been studied in several spiral galaxies but the underlying physics are not yet well understood. M51, as a nearby face-on, grand design…

We report on the results of the first 3D SPH simulation of massive, gravitationally unstable protoplanetary disks with radiative transfer. We adopt a flux-limited diffusion scheme justified by the high opacity of most of the disk. The…

In order to identify the exact criteria for the formation of two-ring structures in galaxies, we studied the issue of gravitational instability of the corresponding structural vibration modes against the background of a composite disk model…

We use a suite of SPH simulations to investigate the susceptibility of protoplanetary discs to the effects of self-gravity as a function of star-disc properties. We also include passive irradiation from the host star using different models…

The spatial distribution of stars in a disk of a galaxy can be described by a radial scale length and a vertical scale height. The ratio of these two scale parameters contains information on the axis ratio of the velocity ellipsoid, i.e.…

In the disk-mediated accretion scenario for the formation of the most massive stars, gravitational instabilities in the disk can force it to fragment. We investigate the effects of inclination and spatial resolution on observable kinematics…

Theoretical and numerical studies have shown that large-scale vortices in Protoplanetary discs can result from various hydrodynamical instabilities. Once produced, such vortices can survive nearly unchanged over a large number of rotation…

In this letter we study the mean sizes of Halpha clumps in turbulent disk galaxies relative to kinematics, gas fractions, and Toomre Q. We use 100~pc resolution HST images, IFU kinematics, and gas fractions of a sample of rare, nearby…

We consider a differentially rotating, 2D stellar disk perturbed by two steady state spiral density waves moving at different patterns speeds. Our investigation is based on direct numerical integration of initially circular test-particle…

We present results of numerical N-body simulations of a galactic stellar disk embedded into a spherical dark halo. The non-linear dynamics of bending instabilities developing in the disk is studied. The bending modes, axisymmetric and not,…

Recent observations show that planet formation is already underway in young systems, when the protostar is still embedded into the molecular cloud and the accretion disc is massive. In such environments, the role of self gravity (SG) and…

We propose a new, more realistic, description of the perturbed gravitational potential of spiral galaxies, with spiral arms having Gaussian-shaped groove profiles. We investigate the stable stellar orbits in galactic disks, using the new…

Gravitationally unstable accretion disks emerge in a variety of astrophysical contexts - giant planet formation, FU Orioni outbursts, feeding of AGNs, and the origin of Pop III stars. When a gravitationally unstable disk is unable to cool…

We argue that gravitational instability of typical protostellar disks is not a viable mechanism for the fragmentation into multiple systems -- binary stars, brown dwarf companions, or gas giant planets -- except at periods above roughly…