Extragalactic stellar streams as astrophysical tools to decipher dark matter

2026-07-22

Stellar streams are sensitive to both the distribution of dark matter and the population of dark matter subhalos in galaxies, which both vary depending on the nature of the dark matter particle. In galaxies beyond the Milky Way, extragalactic systems, we can apply a hierarchical inference approach, where we draw from expected distributions to look at thousands of stellar stream properties in a statistical sense. My proposed research will lay the theoretical groundwork and fill the missing gaps in our knowledge of streams in external galaxies to prepare for the wealth of incoming stellar stream data materializing over the next decade from the Nancy Grace Roman space telescope, the Vera C. Rubin Observatory and Euclid. The objectives of this proposal is: 1) to map where the missing thin stellar streams from globular clusters, which are most sensitive to perturbations from subhalos, are located in external galaxies, 2) to develop tools to recover dark matter potentials from stellar streams in external galaxies, and 3) to place constraints on dark matter substructure through statistical analyses of streams and underdensities in dwarf galaxies. To achieve these objectives, I will analyze publicly released catalogs of globular cluster formation and evolution models, develop numerical techniques to model multiple streams at once in external galaxies, and run state-of-the-art Nbody simulations of disrupting globular clusters in dwarfs. This work will facilitate direct comparisons between upcoming data and models from various dark matter particle candidate predictions. My proposed work provides a fundamental method of mapping the otherwise invisible dark matter, and will impact the interdisciplinary direction of dark matter research, in both particle physics and astrophysics.

Denmark

2025-12-15