Direct Modeling of Star Clusters in Galaxy Formation Simulations

Regents Of The University Of Michigan - Ann Arbor, Ann Arbor MI

Investigators

Abstract

The scientists will numerically simulate the origin of star populations in our Galaxy. The study will include a novel approach to modeling star clusters directly in galaxy formation simulations. They seek to unravel several unsolved puzzles in our understanding of Galactic formation and evolution: (i) What caused multiple generations of stars within massive globular clusters? (ii) What is the fraction of halo stars stripped off globular clusters? (iii) Was the bulge assembled by early mergers or by gradual transformation of the Galactic disk? They will implement the cluster formation and evolution model in the cosmological adaptive-mesh-refinement code (called ART) and run several realizations of Milky Way-sized galaxies with different environment and merger history. ART is a powerful galaxy formation code and already includes non-equilibrium cooling and heating of cosmic gas, non-equilibrium formation and dissociation of molecular hydrogen, thermal, kinetic, and radiative feedback of young stars, transport of ionizing radiation, and other important processes. Inclusion of clustered star formation will add a realistic description of stellar populations, with a well-defined stellar initial mass function and more concentrated feedback on the interstellar medium (ISM). The simulations will produce a rich data model, and will be used to interpret various observations of Galactic clusters and dwarf satellites. They will integrate the simulations into a program of state-of-the-art scientific visualizations of galaxy formation over cosmic time. The visualizations will be designed for display at the University of Michigan Planetarium, and will be viewed by thousands of elementary, middle and high school students in the Detroit metropolitan area.