Related papers: Phase spirals induced by the gas warp
We identify a new dust instability that occurs in warped discs. The instability is caused by the oscillatory gas motions induced by the warp in the bending wave regime. We first demonstrate the instability using a local 1D (vertical) toy…
We analyze the spiral structure that results in a numerical simulation of a galactic disk with stellar and gaseous components evolving in a potential that includes an axisymmetric halo and bulge. We perform a second simulation without the…
During the evolution of a pulsar, various phase transitions may occur in its dense interior, such as superfluid transition, as well as transition to various exotic phases of quantum chromodynamics (QCD). We propose a technique which allows…
Deep HI observations of the outer parts of disc galaxies demonstrate the frequent presence of extended, well-developed spiral arms far beyond the optical radius. To understand the nature and the origin of such outer spiral structure, we…
In a cosmological setting, the disc of a galaxy is expected to continuously experience gravitational torques and perturbations from a variety of sources, which can cause the disc to wobble, flare and warp. Specifically, the study of…
Warped disks are almost ubiquitous among spiral galaxies. Here we revisit and test the `fly-by scenario' of warp formation, in which impulsive encounters between galaxies are responsible for warped disks. Based on N-body simulations, we…
Growing observational evidence suggests that Class II protoplanetary disks may undergo substantial interactions with their environment in the form of late infall. This mass inflow predominantly manifests itself in the form of so-called…
Any perturbation to a disc galaxy that creates a misalignment between the planes of the inner and outer disc, will excite a slowly evolving bending wave in the outer disc. The torque from the stiff inner disc drives a retrograde,…
We have applied our method for weighing the Galactic disk using phase-space spirals to the Gaia EDR3 proper motion sample. For stars in distant regions of the Galactic disk, the latitudinal proper motion has a close projection with vertical…
The recent discovery of a spiral pattern in the vertical kinematic structure in the solar neighborhood provides a prime opportunity to study non-equilibrium dynamics in the Milky Way from local stellar kinematics. Furthermore, results from…
We develop a novel method to simultaneously determine the vertical potential, force and stellar $z-v_z$ phase space distribution function (DF) in our local patch of the Galaxy. We assume that the Solar Neighborhood can be treated as a…
Spiral wave, whose rotation center can be regarded as a point defect, widely exists in various two dimensional excitable systems. In this paper, by making use of \emph{Duan's topological current theory}, we obtain the charge density of…
High resolution N-body simulations using different codes and initial condition techniques reveal two different behaviours for the rotation frequency of transient spiral arms like structures. Whereas unbarred disks present spiral arms nearly…
Understanding the spiral arms of the Milky Way (MW) remains a key open question in galactic dynamics. Tidal perturbations, such as the recent passage of the Sagittarius dwarf galaxy (Sgr), could play a significant role in exciting them. We…
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…
Gas in disk galaxies interacts nonlinearly with an underlying stellar spiral potential to form galactic spiral shocks. While numerical simulations typically show that spiral shocks are unstable to wiggle instability (WI) even in the absence…
The rate of internally-driven evolution of galaxy discs is strongly affected by the lifetimes of the spiral patterns they support. Evolution is much faster if the spiral patterns are recurrent short-lived transients rather than long-lived,…
Asymmetries in galactic potentials, either self-induced, or caused by a passing companion, play an important role in global gas dynamics in galaxies. In particular, they are able to trigger gas inflow, which in turn feeds nuclear activity.…
Spiral density waves generated by an embedded planet are understood to cause ``kinks'' in observed velocity channel maps of CO surface emission, by perturbing the gas motion within the spiral arms. If velocity kinks are a reliable probe of…
Magnetic fields in nearby, star-forming galaxies reveal both large-scale patterns and small-scale structures. A large-scale field reversal may exist in the Milky Way but no such reversals have been observed so far in external galaxies. The…