Realistic star cluster simulations that dynamically evolve embedded star clusters require an accurate treatment of the stars, gas and their interaction. We present and validate a novel technique which creates an initial gas density distribution based on observational gas column density data. We consider two approaches to this technique where the first is based on randomly sampling from the original gas density distribution and the second assigns one particle to represent the gas in each observed image pixel. To create a three-dimensional distribution, we consider two estimates of cloud depth where one is a constant value and the second involves variable depths calculated using image processing techniques based on density features seen in the plane of the sky. We apply these methods to evolve the Carina region using initial stellar positions derived from the MYSTiX catalogue and gas data from the Herschel Hi-GAL survey. We evolve the stars using an N-body code and the gas using a smoothed-particle hydrodynamics code which are coupled through the AMUSE framework. We analyzed our results using dendrograms to describe the gas distribution over time and the DBSCAN clustering algorithm to track the clustering of stars over time. We model the gas using an adiabatic ideal gas equation of state and find that increasing the initial gas velocity dispersion prevents gas from accumulating and therefore could hinder future star formation. We also find that the stars, initially in subclusters spatially (not necessarily bound), tend to merge together to form one large cluster regardless of the initial conditions of the gas. It is only after the subclusters have merged that the initial conditions of the gas start to have a noticeable effect on the structure of the star cluster. Of the two approaches to our novel technique, the second approach leads to more accurate and realistic results. The second approach also has a significant effect on the stars as the subclusters merge together approximately 1 Myr earlier compared to the first approach. Therefore the choice of initial gas conditions affects the dynamical evolution of star cluster systems and being able to incorporate observational gas data leads to the increasingly accurate dynamical evolution of such systems. / Thesis / Master of Science (MSc)
| Identifer | oai:union.ndltd.org:mcmaster.ca/oai:macsphere.mcmaster.ca:11375/25967 |
| Date | January 2020 |
| Creators | Mathews, Anita |
| Contributors | Sills, Alison, Physics and Astronomy |
| Source Sets | McMaster University |
| Language | English |
| Detected Language | English |
| Type | Thesis |
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