On the origin of the clumpy streams of Palomar 5
  In this paper we report a study (see Mastrobuono-Battisti et al., 2012) about
the formation and characteristics of the tidal tails around Palomar 5 along its
orbit in the Milky Way potential, by means of direct N-body simulations and
simplified numerical models. Unlike previous findings, we are able to reproduce
the substructures observed in the stellar streams of this cluster, without
including any lumpiness in the dark matter halo. We show that overdensities
similar to those observed in Palomar 5 can be reproduced by the epicyclic
motion of stars along its tails, i.e. a simple local accumulation of orbits of
stars that escaped from the cluster with very similar positions and velocities.
This process is able to form stellar clumps at distances of several kiloparsecs
from the cluster, so it is not a phenomenon confined to the inner part of
Palomar 5's tails, as previously suggested.
