16 research outputs found
A Dynamical Model of the Inner Galaxy
An extension of Schwarzschild's galaxy-building technique is presented that,
for the first time, enables one to build Schwarzschild models with known
distribution functions (DFs). The new extension makes it possible to combine a
DF that depends only on classical integrals with orbits that respect
non-classical integrals. With such a combination, Schwarzschild's orbits are
used only to represent the difference between the true galaxy DF and an
approximating classical DF. The new method is used to construct a dynamical
model of the inner Galaxy. The model is based on an orbit library that contains
22168 regular orbits. The model aims to reproduce the three-dimensional mass
density of Binney, Gerhard & Spergel (1997), which was obtained through
deprojection of the COBE surface photometry, and to reproduce the observed
kinematics in three windows - namely Baade's Window and two off-axis fields.
The model fits essentially all the available data within the innermost 3 kpc.
The axis ratio and the morphology of the projected density contours of the COBE
bar are recovered to good accuracy within corotation. The kinematic quantities
- the line-of-sight streaming velocity and velocity dispersion, as well as the
proper motions when available - are recovered, not merely for the fitted
fields, but also for three new fields. The dynamical model deviates most from
the input density close to the Galactic plane just outside corotation, where
the deprojection of the surface photometry is suspect. The dynamical model does
not reproduce the kinematics at the most distant window, where disk
contamination may be severe.Comment: 20 pages, 5 gif figures, 11 postscript figures, submitted to MNRAS.
Zipped postscript available at
http://www-thphys.physics.ox.ac.uk/users/RalfHafner/paper.ps.g
Learning of Visual Navigation Strategies
Hafner VV, Möller R. Learning of Visual Navigation Strategies. In: Quoy M, Gaussier P, Wyatt J, eds. Proc. European Workshop of Learning Robots (EWLR-9), Prague. 2001: 47-56