"What Can Stellar Streams Tell Us About Dark Matter?"

Stellar streams, thin stellar structures formed by tidal stripping of globular clusters or dwarf galaxies, are among the most sensitive probes of dark matter substructure on small scales, where the microphysical nature of dark matter could leave distinct signatures. During the talk, I will review current analysis methods and observational constraints. I will then present a JAX-based fully differentiable forward model that operates in the diffusion regime, where velocity kicks from many encounters with low-mass substructure accumulate as a random walk over the stream's lifetime. I will show validation of the framework against analytical predictions where available, and present preliminary Fisher forecasts for a GD-1--like stream, quantifying the expected sensitivity of current and upcoming data to the properties of dark matter substructure.