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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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