Bekdaulet Shukirgaliyev

Bekdaulet Shurkirgaliyev  ( Kazakhstan )

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Comprehensive modeling of the evolution of star clusters

Star clusters form in dense clumps of gas inside giant molecular clouds. The dynamics of stars in young star clusters during their formation and after gas expulsion is not fully understood yet. Also, the absence of the mass-radius relation of young star clusters remains heavily debated. The main goal of my thesis is to model the violent relaxation of young star clusters after residual star-forming gas expulsion, in particular to quantify the stellar mass they lose and the degree of expansion they experience following gas expulsion. We start from the semi-analytical model of local-density-driven clustered star formation. This model yields a spatial density profile for the newly-formed star cluster steeper than for its precursor gas clump, which is as observed in star-forming regions of the Solar Neighborhood. We will explore the hypothesis that a density profile steeper for the cluster than for the gas enhances the cluster survival likelihood compared to a model where the density profiles of the embedded cluster and of the gas have the same. We use direct n-body simulation methods for our numerical models. We intend to make series of simulations with different initial masses, density profiles within the (from the very weak to the strongest) tidal field of the host galaxy. Our simulations will allow us to quantify the response of the star cluster to instantaneous gas expulsion, the dependence of the star cluster bound fraction on the global star formation efficiency, the conditions of star cluster survival or dissolution and to explore under what conditions one can reproduce the absence of a mass-radius relation for young star clusters.

Supervisor:   Genevieve Parmentier   ( ARI )

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