Abstract
Stellar streams have proven to be powerful tools for measuring the Milky
Way's gravitational potential and hence its dark matter halo. In the coming
years, Vera Rubin, Euclid, ARRAKIHS, and NGRST will uncover a plethora of
streams around external galaxies. Although great in number, observations of
these distant streams will often be limited to only the on-sky position of the
stream. In this work, we explore how well we will be able to measure the dark
matter haloes of these galaxies by fitting simplified mock streams with a
variety of intrinsic and orbital properties in a range of data availability
scenarios. We find that streams with multiple wraps around their host galaxy
can constrain the overall radial profile and scale radius of the potential
without radial velocities. In many other cases, a single radial velocity
measurement often provides a significant boost to constraining power for the
radial profile, scale radius, and enclosed mass of the dark matter halo. Given
the wealth of data expected soon, this suggests that we will be able to measure
the dark matter haloes of a statistically significant sample of galaxies with
stellar streams in the coming years.