Title: Quantifying tidal stream disruption in a simulated Milky Way,
Abstract: Simulations of tidal streams show that close encounters with dark matter
subhalos induce density gaps and distortions in on-sky path along the streams.
Accordingly, observing disrupted streams in the Galactic halo would
substantiate the hypothesis that dark matter substructure exists there, while
in contrast, observing collimated streams with smoothly varying density
profiles would place strong upper limits on the number density and mass
spectrum of subhalos. Here, we examine several measures of stream "disruption"
and their power to distinguish between halo potentials with and without
substructure and with different global shapes. We create and evolve a
population of 1280 streams on a range of orbits in the Via Lactea II simulation
of a Milky Way-like halo, replete with a full mass range of {\Lambda}CDM
subhalos, and compare it to two control stream populations evolved in smooth
spherical and smooth triaxial potentials, respectively. We find that the number
of gaps observed in a stellar stream is a poor indicator of the halo potential,
but that (i) the thinness of the stream on-sky, (ii) the symmetry of the
leading and trailing tails, and (iii) the deviation of the tails from a
low-order polynomial path on-sky ("path regularity") distinguish between the
three potentials more effectively. We find that globular cluster streams on
low-eccentricity orbits far from the galactic center (apocentric radius ~ 30-80
kpc) are most powerful in distinguishing between the three potentials. If they
exist, such streams will shortly be discoverable and mapped in high dimensions
with near-future photometric and spectroscopic surveys.