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Stellar mass-loss in the dynamics of galaxies
Křížek, Miroslav
Title: Stellar mass-loss in galactic dynamics Author: Miroslav Křížek Department: Astronomical Institute of the Charles University Supervisor: RNDr. Bruno Jungwiert, Ph.D., Astronomical Institute - Academy of Sciences of the Czech Republic, v.v.i. and University of California - Riverside Supervisor's e-mail address: bruno@ig.cas.cz Abstract: We present an implementation of the statistical approach to the stars-gas mass exchange cycle into the N-body code. First, we summarize available data on stellar mass-loss and derive the time-dependency of the mass-loss rate of a single stellar population. Since the adopted probabilistic scheme that served as a basis for our implementation was limited to the linear star formation law while observations seem to suggest a non-linearity, we derive the non-linear star formation scheme. Both sides of the mass exchange cycle are then implemented into the code with stellar and gaseous particles and compared with an analytic recipe to test their reliability. In the next step, the comparison of such an extended statistical approach with deterministic scheme is performed for a fully dynamical model. The aim of such comparison is to explore divergence between both models of different natures. As illustration of the code application and sensitivity of the resulting galaxy disk...
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Stellar mass-loss in the dynamics of galaxies
Křížek, Miroslav
Title: Stellar mass-loss in galactic dynamics Author: Miroslav Křížek Department: Astronomical Institute of the Charles University Supervisor: RNDr. Bruno Jungwiert, Ph.D., Astronomical Institute - Academy of Sciences of the Czech Republic, v.v.i. and University of California - Riverside Supervisor's e-mail address: bruno@ig.cas.cz Abstract: We present an implementation of the statistical approach to the stars-gas mass exchange cycle into the N-body code. First, we summarize available data on stellar mass-loss and derive the time-dependency of the mass-loss rate of a single stellar population. Since the adopted probabilistic scheme that served as a basis for our implementation was limited to the linear star formation law while observations seem to suggest a non-linearity, we derive the non-linear star formation scheme. Both sides of the mass exchange cycle are then implemented into the code with stellar and gaseous particles and compared with an analytic recipe to test their reliability. In the next step, the comparison of such an extended statistical approach with deterministic scheme is performed for a fully dynamical model. The aim of such comparison is to explore divergence between both models of different natures. As illustration of the code application and sensitivity of the resulting galaxy disk...
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Velocity dispersion in open clusters
Zimandl, Martin ; Šubr, Ladislav (advisor) ; Jungwiert, Bruno (referee)
There have been measured higher values of velocity dispersion in cores of some open clusters, than was expected for cluster in virial equilibrium. In this writing we'll try to find causes of this effect. To do that, we'll look into two computed numerical models of open clusters, wich shows similiar diversion. On simple observations and statistical analysis we'll design methods to accurately calcula te velocity dispersion and afterwards we'll verify correctness of these methods. Then we'll use these methods to investigate evolution of velocity dispersion in both used models of open clusters. 1
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