Dwarf Galaxies, Abundance Distributions and the Physics of Galaxy Formation

Columbia University, New York NY

Investigators

Abstract

Dr. Johnston and her co-investigators will perform a comprehensive set of simulations to follow the chemical and dynamical evolution of dwarf galaxies, the most common type of galaxy in our local Universe. The simulations will include a broad range of relevant physics including the buildup of chemical elements heavier than helium, which are produced by nuclear reactions in stars and released to the interstellar gas as the stars end their lives. The team will first identify where a dwarf galaxy forms within a large-scale cosmological simulation, and then re-run that patch of the simulation at much higher resolution with the hydrodynamic code ENZO. This code, largely developed by co-investigator Bryan, provides a higher-fidelity treatment of interstellar gas dynamics and mixing than competing methods. The group will include a new and computationally efficient method to calculate the gas cooling caused by elements with atomic numbers up to Z=30. At its highest resolution, the ENZO code will follow gas dynamics on a scale of 3-4 light years, and can include enough stellar particles to follow all individual stars with at least half the Sun's mass. Dwarf galaxies are normally found close to more luminous galaxies, which can affect their formation and evolution; the team will use their simulations to examine these processes. A graduate student and a postdoctoral fellow will be trained by their involvement in the research. Dr. Johnston and her co-investigators will produce visualizations from this project, to be shown to the public at the American Museum of Natural History, where Dr. Mac Low is a tenured curator. Dr. Johnston also chairs the Vice Provost's Taskforce for Diversity in Science and Engineering at Columbia, and is active in outreach to schoolgirls.