Extragalactic streams & dark matter
We are about to enter an exciting new era, where data of thousands of streams orbiting other galaxies will become available over the course of the next five years facilitated by the European Space Agency’s space-based survey mission, Euclid, the ground-based Vera C. Rubin Observatory (Rubin), and the Nancy Grace Roman Space Telescope (Roman). Pearson recently showed that it is feasible to use extragalactic stellar streams to learn about the dark matter halos of host galaxies (Pearson et al. 2022b). She modeled the Dwarf3 stellar stream in Centaurus A's halo (see image) and used it to set a lower limit on the dark matter mass of the host galaxy. This provides preliminary evidence that dark matter can be mapped in external galaxies with stellar streams. She found that there are many viable stream models that fit the data well, provided that Cen A has a halo mass larger than M200 > 4.70 × 10^12 Msun.