Related papers: Radial disk heating by more than one spiral densit…
We explore the heating of the velocity distribution in the solar neighbourhood by stochastic spiral waves. Our investigation is based on direct numerical integration of initially circular test-particle orbits in the sheared sheet. We…
We use the marginal stability condition for galactic disks and the stellar velocity dispersion data published by different authors to place upper limits on the disk local surface density at two radial scalelengths $R=2h$. Extrapolating…
We argue that self-excited instabilities are the cause of spiral patterns in simulations of unperturbed stellar discs. In previous papers, we have found that spiral patterns were caused by a few concurrent waves, which we claimed were…
We describe a new mechanism that leads to the destabilisation of non-axisymmetric waves in astrophysical discs with an imposed radial temperature gradient. This might apply, for example, to the outer parts of protoplanetary discs. We use…
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…
We present results from a detailed dynamical analysis of five high surface brightness, late type spirals, studied with the aim to quantify the luminous-to-dark matter ratio inside their optical radii. The galaxies' stellar light…
We use hydrodynamic simulations to investigate nonlinear gas responses to an imposed stellar spiral potential in disk galaxies. The gaseous medium is assumed to be infinitesimally thin, isothermal, and unmagnetized. We consider various…
We investigate both analytically and numerically the motion of massless particles orbiting primary star in a close circular binary system with particular focus on the gas drag effects. These are the first calculations with particles ranging…
Frankel et al (2020) reported that the rate of diffusion in angular momentum by stars in the disk of the Milky Way was about ten times faster than the rate of heating, which places a stringent requirement on the nature of disk star…
The present study of the two-stream instability in stellar disks with counter-rotating components of stars and/or gas is stimulated by recently discovered counter-rotating spiral and S0 galaxies. Strong linear two-stream instability of…
We expand our pervious numerical study of the properties of the stellar velocity distribution within the disk of a two-armed spiral galaxy by considering spiral stellar density waves with different global Fourier amplitudes, C_2. We confirm…
We investigate the possibility of describing the spiral pattern of the Milky Way in terms of a model of superposition 2- and 4-armed wave harmonics (the simplest description, besides pure modes). Two complementary methods are used: a study…
The dynamical nature and formation mechanism(s) of galactic spiral arms remain long-standing problems in astrophysics. Most theoretical work is based on analytic calculations or idealised simulations, which has yielded several theories of…
We run N-body smoothed particle hydrodynamics (SPH) simulations of a Milky Way sized galaxy. The code takes into account hydrodynamics, self-gravity, star formation, supernova and stellar wind feedback, radiative cooling and metal…
We present initial attempts to include the multi-dimensional nature of radiation transport in hydrodynamical simulations of the small-scale structure that arises from the line-driven instability in hot-star winds. Compared to previous 1D or…
We explore the secular dynamical evolution of an N-body model of M31 in the presence of a population of 100 dark matter satellites over 10 Gyr. The satellite population has structural and kinematic characteristics modelled to follow the…
Previous research has established a relationship between radial action and scale height in Galactic disks, unveiling a correlation between radial and vertical heating. This finding poses a challenge to our existing comprehension of heating…
We study particle dynamics in local two-dimensional simulations of self-gravitating accretion discs with a simple cooling law. It is well known that the structure which arises in the gaseous component of the disc due to a gravitational…
We use numerical simulations to examine the effects of radial migration on the vertical structure of galaxy disks. The simulations follow three exponential disks of different mass but similar circular velocity, radial scalelength, and…
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…