Stellar orbits in a non-axisymmetric potential

• Grant number: 05/55735-9
• Support Opportunities: Scholarships in Brazil - Post-Doctoral
• Start date: December 01, 2005
• End date: November 30, 2006
• Field of knowledge: Physical Sciences and Mathematics - Astronomy - Positional Astronomy and Celestial Mechanics
• Principal Investigator: Jacques Raymond Daniel Lépine
• Grantee: Sebastien Gilles Marcel Picaud
• Host Institution: Instituto de Astronomia, Geofísica e Ciências Atmosféricas (IAG). Universidade de São Paulo (USP). São Paulo , SP, Brazil

Abstract

The proposed work consists in the building of self-consistent dynamical models of non-axisymmetric rotating stellar structures (spiral arms, bar...) observed in the Milky Way and other spiral galaxies. The chosen method is based on the extraction of closed stellar orbits in the rotating frame and the deduction from these orbits of the implied density directly comparable with the density deduced from the modelled potential formula. The self-consistency happens when these two densities coincide, which, in physical terms, means that the structure is viable for a rather long period and therefore can correspond to an observed feature. The program, constructed during a first year of post-doctoral position, is almost finished. We plan to complete its building and apply it to study 3 different non-axisymmetric structures which exist or may exist in our Galaxy: a 4-arm spiral structure, a weak boxy shaped bar, and a "single peak" perturbation. The study of these models will permit the determination of the values of the parameters which give the best self-consistency, and the use of these results to extract some informations about the possible length, shape or pattern speed of the different non-axisymmetric structures of the Milky Way, and the eventual links between them. (AU)