Christian Aganze - Detecting Gaps in Globular Cluster Streams in M31 and Other External Galaxies with the Nancy Grace Roman Telescope

Cosmological simulations that include dark matter predict the existence of low-mass subhalos. These subhalos can perturb thin stellar streams formed by tidal disruption of globular clusters (GCs), creating a gap-like feature like those detected in Gaia data (e.g GD-1). While the gap morphology offers an avenue for constraining different dark matter models, the sample of GC streams in the Galaxy with confirmed gaps remains small due to the streams’ intrinsic low surface brightness. Previously, Pearson et al. (2021) have shown that the Nancy Grace Roman Space Telescope (Roman) will detect thin streams in external galaxies originating from GCs with progenitor GC masses as low as ~ 5x104 solar masses. It is unknown, however, if we can observe gaps in these streams in external galaxies. UCSD's Christian Aganze will present our work on predicting the detectability of gaps in GC streams in the halo of M31 and other external galaxies with the Nancy Grace Roman Telescope. We generate mock streams and we model subsequent subhalo interactions in thin streams orbiting in a model potential for M31, with initial GC masses of 5x104 solar masses and subhalo masses of 105-107 solar masses. We study the gaps created through the interaction between these subhalos and GC streams and predict detectability thresholds for these gaps by incorporating realistic background stars simulated in the Roman 0.28 deg2 field of view projected to the distance of M31 and other nearby galaxies.