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OATS-DAUT SEMINAR
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Speaker:
Christian Theis
(Institut fur Astronomie, Universitat Wien)
Title:
Modeling Interacting Galaxies
Date: Wednesday, May 2nd, 2007
Time: 12:00
Venue: Villa Bazzoni
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Abstract:
Interacting galaxies are among the most fascinating objects in the
universe. Their morphology is frequently characterized by clear
indications for an interaction, e.g. by large-scale features denoted
as "arms", "bridges" or "rings". In principle, this wealth of
information could be sufficient to restrict or fix the dynamical
history of interacting galaxies and/or to allow for conclusions about
their internal structure, e.g. their dark matter
distribution. Unfortunately, an interaction between galaxies depends
on many parameters which usually prohibits classical modelling
strategies, e.g. those based on complete grids in parameter
space. Additionally, state-of-the-art models of galactic evolution
should not only include stellar dynamics, but also (multi-phase) gas
dynamics, star formation and feedback processes. Such models are more
complex from a conceptional point of view and they are computationally
expensive.
In my talk I will discuss the problems related to theoretical
modelling of interacting galaxies. I will present a multi-method
modelling strategy: as a first step a new modelling technique for the
analysis of observed interacting galaxies is applied. The method is
based on a combination of an evolutionary search strategy (a genetic
algorithm) with a fast restricted N-body simulation method. I will
demonstrate the applicability of this approach for providing both, a
uniqueness test of preferred interaction scenarios and an automatic
fitting procedure for sufficiently detailed observations. As a second
step the models will be refined by self-consistent models, which are
based either on pure stellardynamical calculations or on full galactic
evolutionary models including gas dynamics, star formation and
feedback mechanisms.
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