Related papers: Parker Instability in a Self-Gravitating Magnetize…
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…
A substantial fraction of the warps in spiral galaxies may result from bending instabilities if the disks are essentially self-gravitating. With N-body simulations, we show that galaxies with self-gravitating disks as thick as HI disks are…
We present an instability occurring in the inner part of disks threaded by a moderately strong vertical (poloidal) magnetic field. Its mechanism is such that a spiral density wave in the disk, driven by magnetic stresses (rather than…
Low-mass condensations (LMCs) are observed inside the envelope of the collapsing molecular cloud cores. In this research, we investigate the effects of landing LMCs for occurrence of instability through the protostellar accretion disks. We…
Hydrostatic equilibrium of the multiphase interstellar medium in the solar vicinity is reconsidered, with the regular and turbulent magnetic fields treated separately. The regular magnetic field strength required to support the gas is…
The density structure of the interstellar medium (ISM) determines where stars form and release energy, momentum, and heavy elements, driving galaxy evolution. Density variations are seeded and amplified by gas motion, but the exact nature…
The gravitational three-body problem is a fundamental problem in physics and has significant applications to astronomy. Three-body configurations are often considered stable as long the system is hierarchical; that is, the two orbital…
We study local radiation magnetohydrodynamic instabilities in static, optically thick, vertically stratified media with constant flux mean opacity. We include the effects of vertical gradients in a horizontal background magnetic field.…
We review the models and results of simulations of self-gravitating, gaseous protoplanetary disks in binary star systems. These models have been calculated by three different groups with three different computational methods, two…
There exist many physical processes that may contribute to the driving of turbulence in galactic disks. Some of them could drive turbulence even in the absence of star formation. For example, hydrodynamic (HD) or magnetohydrodynamic (MHD)…
Forming giant planets by disk instability requires a gaseous disk that is massive enough to become gravitationally unstable and able to cool fast enough for self-gravitating clumps to form and survive. Models with simplified disk cooling…
The morphology of gas-rich disc galaxies at redshift ~1-3 is dominated by a few massive clumps. The process of formation or assembly of these clumps and their relation to molecular clouds in contemporary spiral galaxies are still unknown.…
Spiral shocks are potentially a major source of turbulence in the interstellar medium. To address this problem quantitatively, we use numerical simulations to investigate gas flow across spiral arms in vertically stratified,…
Nonlinear numerical simulations are performed to investigate the density evolution in the dust layer of a protoplanetary disk due to the gravitational instability and dust settling toward the midplane. We assume the region where the radial…
We analyze the stability of dust layer in protoplanetary disk to understand the effect of the relative motion between gas and dust. The previous analyses not including the effect of relative motion between gas and dust show that the…
We study the linear evolution of small perturbations in self-gravitating fluid systems with magnetic fields. We consider wave-like perturbations to nonuniform filamentary and sheet-like hydrostatic equilibria in the presence of a uniform…
Galaxy clusters show large-scale azimuthal X-ray surface brightness fluctuations known as cold fronts. Cold fronts are argued to originate due to sloshing driven by sub-halo passage at close proximity to the cluster center. While this…
Thin, Keplerian accretion disks generically become gravitationally unstable at large radius. I investigate the nonlinear outcome of such instability in cool disks using razor-thin, local, numerical models. Cooling, characterized by a…
We establish the linear instability of the semiclassical Einstein-Klein-Gordon system linearised about the Minkowski vacuum spacetime. The proof relies on formulating a forcing problem for both metric and state perturbations within the…
We investigate giant molecular cloud (GMCs) collisions and their ability to induce gravitational instability and thus star formation. This mechanism may be a major driver of star formation activity in galactic disks. We carry out a series…