Variation in the Stellar Mass Function Along Stellar Streams
  Stellar streams are the inevitable end product of star cluster evolution,
with the properties of a given stream being related to its progenitor. We
consider how the dynamical history of a progenitor cluster, as traced by the
evolution of its stellar mass function, is reflected in the resultant stream.
We generate model streams by evolving star clusters with a range of initial
half-mass relaxation times and dissolution times via direct N-body simulations.
Stellar streams that dissolve quickly show no variation in the stellar mass
function along the stream. Variation is, however, observed along streams with
progenitor clusters that dissolve after several relaxation times. The mass
function at the edges of a stream is approximately primordial as it is
populated by the first stars to escape the cluster before segregation occurs.
Moving inwards the mass function steepens as the intermediate parts of the
stream consist of mostly low-mass stars that escaped the cluster after some
segregation has occurred. The centre of the stream is then marked by a flatter
mass function, as the region is dominated by high-mass stars that quickly
segregated to the progenitor cluster's centre and were the last stars to become
unbound. We further find that the maximum slope of the mass function along the
stream and the rate at which it decreases with distance from the dissolved
progenitor serve as proxies for the dynamical state reached by the progenitor
cluster before dissolution; this may be able to be applied to observed streams
with near-future observations.
