ELFT HÍRADÓ

[StatFizSzeminar <statfiz AT glu.elte.hu>]

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                   ELTE Institute of Physics
                SEMINARS IN STATISTICAL PHYSICS


                       24th February 2016
                       Wednesday, 11 a.m.

                         Christof Jung

                 Instituto de Ciencias Físicas,
            Universidad Nacional Autónoma de México

             "The role of NHIMs in barred galaxies"


The effective potential in the rotating frame for a barred galaxy has two
index-1 saddle points. They are the Lagrange points L2 and L3. Their positions
are approximately the ends of the bar. For energies a little above the saddle
energy the phase space contains normally hyperbolic invariant manifolds
( NHIMs ) sitting over the saddle points. The stable and unstable manifolds of
the NHIMs direct and channel the flow over the saddles. The outer branches of
the unstable manifolds trace out the ring and spiral structures of the galaxy
going out from the ends of the bar. We can imagine how these structures are
formed by the perturbations created by the stars leaking out from the interior
part of the galaxy over the saddles and moving along the unstable manifolds of
the NHIMs.


                          Room 2.54
     1117 Budapest, Pázmány P. sétány 1/A (Northern Block)
              home page: http://glu.elte.hu/~statfiz


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