Related papers: Exponential Disks from Stellar Scattering: III. St…
Spirals in galaxies have long been thought to be caused by gravitational instability in the stellar component of the disk, but discerning the precise mechanism had proved elusive. Tidal interactions, and perhaps bars, may provoke some…
The circular velocities of the inner region of disk galaxies are predicted by standard physics but velocities beyond the stellar disks are not consistent with Newtonian physics if the material there is in stable circular orbits. However,…
We present new models for the formation of disk galaxies that improve upon previous models by following the detailed accretion and cooling of the baryonic mass, and by using realistic distributions of specific angular momentum. Under the…
A theory is developed for the dynamics of eccentric perturbations $[\propto \exp(\pm i\phi)]$ of a disk galaxy residing in a spherical dark matter halo and including a spherical bulge component. The disk is represented as a large number $N$…
In this paper we revisit the "eccentric disc instability", an instability which occurs in coherently eccentric discs of stars orbiting massive black holes (MBHs) embedded in stellar clusters, which results in stars achieving either very…
A model of a galactic disk is presented which extends the homogeneous one zone models by incorporating propagation of material and energy in the disk. For reasonable values of the parameters the homogeneous steady state is unstable to the…
We present here a self-consistent, tridimensional model of a disc galaxy composed by a number of ellipsoidal distributions of matter having different flattening and density profile. The model is self-consistent and takes into account the…
We present the first results of a systematic analysis of radially truncated exponential discs for four galaxies of a complete sample of disc-dominated edge-on spiral galaxies. The discs of our sample galaxies are truncated at similar radii…
The formation of galactic discs and the efficiency of star formation within them are issues central to our understanding of galaxy formation. We have developed a detailed and versatile model of disc formation which combines the strengths of…
We investigate the two-dimensional classical dynamics of the scattering of point particles by two periodically oscillating disks. The dynamics exhibits regular and chaotic scattering properties, as a function of the initial conditions and…
The surface-brightness profiles of galaxy disks fall into three main classes, based on whether they are simple exponentials (Type I), bend down at large radii (Type II, "truncations") or bend up at large radii (Type III, "antitruncations").…
We investigate the process of an inhomogeneous planetesimal disk evolution caused by the planetesimal-planetesimal gravitational scattering. We develop a rather general approach based on the kinetic theory which self-consistently describes…
Disk galaxies evolve over time through processes that may rearrange both the radial mass profile and the metallicity distribution within the disk. This review of such slow changes is largely, though not entirely, restricted to…
Galactic discs are known to have exponential radial profiles in luminosity and stellar surface density in their bright inner regions. Nonetheless, their faint outer regions often display a break, with either a down-bending or an up-bending…
Binary stars produce an array of dramatic astrophysical phenomena. They allow us to probe stellar structure, nuclear physics, and gravitational wave physics. They also produce the powerful supernovae that allow us to measure the scale of…
We examine the growth of eccentricities of a population of particles with initially circular orbits around a central massive body. Successive encounters between pairs of particles increase the eccentricities in the disk on average. As long…
We report here the first evidence for stellar disk truncation at high redshift, based on surface photometry of a sample of 16 high redshift (0.6 < z < 1.0) disk galaxies from the GOODS HST/ACS data. The radial profiles are best fit by a…
The absence of stellar disc truncations in low-inclined spiral galaxies has been a matter of debate in the last decade. Disc truncations are often observed in highly inclined galaxies but no obvious detection of this feature has so far been…
Recent theoretical work suggests that it may be common for stars in the disks of spiral galaxies to migrate radially across significant distances in the disk. Such migrations are a result of resonant scattering with spiral arms and move the…
We demonstrate that shadows cast on a proto-planetary disk can drive it eccentric. Stellar irradiation dominates heating across much of these disks, so an uneven illumination can have interesting dynamical effects. Here, we focus on…