Nikos Voglis

TL;DR: In this article, it was shown that in deterministic dynamical systems any orbit is associated with an invariant spectrum of stretching numbers, i.e. numbers expressing the logarithmic divergences of neighbouring orbits within one period.

TL;DR: In this paper, the authors demonstrate how the projection of unstable manifolds in configuration space reproduces essentially the entire observed bar-spiral pattern in a N-body simulation of a barred spiral galaxy.

TL;DR: In this paper, the authors examined the mass in regular and chaotic motion of rotating galaxies and showed that the spatial distribution of these two sets of particles is much different, and that the fraction of mass in chaotic motion in the non-rotating iso-energetic model is much larger than in the rotating model.

TL;DR: In this article, the authors estimate the two-point correlation function in redshift space of the recently compiled HI Parkes All-Sky Survey neutral hydrogen (HI) sources catalogue, which if modelled as a power law, xi(r) = (r(0)/r)(gamma), the best-fitting parameters for the HI selected galaxies are found to be r(0) = 3.3 +/- 0.3 h(-1) Mpc with gamma = 1.8 +/- 1.24.

TL;DR: In this article, the authors studied the relation between the forms of the sticky region and asymptotic curves and found that the crossing of the cantori by periodic orbits of periodic orbits just inside the cantorus can finally extend to large distances outwards.