Collaborative Research: Constraining Dark Matter with Globular Clusters and Stellar Streams

About This Grant

The fundamental nature of dark matter, the largest and most mysterious component of galaxies, remains one of the key questions of modern physics. Wide-field surveys such as those planned by the Rubin Observatory, the Euclid Mission, and the Roman Space Telescope will fundamentally change our understanding of the nature of dark matter. One such change will come from the ability of these surveys to discover large numbers of stellar streams: delicate trails of stars created when star clusters are pulled apart by the gravity of their parent galaxy. These streams are extremely sensitive tracers of the parent’s gravitational potential. Since galaxies’ gravity comes mostly from their dark matter, streams present a unique opportunity to probe dark matter’s properties. A team of scientists from the University of North Carolina, the University of Pennsylvania, and Northwestern University, will be the first to combine supercomputer simulations of both the galaxies and the star clusters themselves to study how these clusters form, live, and create stellar streams in galaxies with different quantities and forms of dark matter. The project’s main goal is to create a dark matter “spotters guide” for stellar streams, which can be used to understand the deluge of data coming from next-generation telescopic surveys. As part of this project, the team will lead the development of an interactive virtual reality (VR) program for middle school students, based on the simulated star clusters and streams, designed to educate the public on the nature of dark matter, its relationship to the evolution of galaxies and their star clusters, and the exciting science potential of these upcoming survey instruments. The goal of this project is to develop a self-consistent model of globular cluster formation and evolution in a cosmologically evolving galaxy and use it to predict the properties of globular clusters (GCs) and their streams for next-generation surveys. The project will build upon an existing model for the formation of globular clusters based on zoomed cosmological-hydrodynamical simulations, combining galaxy simulations with star-by-star N-body simulations of clusters to fully resolve this multi-scale problem. The team will implement this model for a suite of cosmological simulations with consistent baryonic physics and alternative dark matter models, e.g. self-interacting dark matter and atomic dark matter. The team will also produce full synthetic observations of GCs and thin stellar streams in external galaxies, their morphology, and their stellar populations, and the cosmologically motivated host stellar halos. The plan is to connect the detectable set of clusters and streams to the origin and evolution of their host environment and the underlying dark matter model. The result will, for the first time, predict self-consistent cluster and stream populations for varying dark matter models, providing a crucial dataset for the interpretation of next generation astronomical surveys such as Rubin, Roman and Euclid. This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.