Simulated {\Lambda}CDM analogues of the thin Plane of Satellites around
  the Andromeda galaxy are not kinematically coherent structures
  A large fraction of the dwarf satellites orbiting the Andromeda galaxy are
surprisingly aligned in a thin, extended and apparently kinematically coherent
planar structure. Such a structure is not easily found in simulations based on
the Cold Dark Matter model ({\Lambda}CDM). Using 21 high resolution
cosmological simulations we analyse the kinematics of planes of satellites
similar to the one around Andromeda. We find good agreement when co-rotation is
characterized by the line-of-sight velocity. At the same time, when co-rotation
is inferred by the angular momenta of the satellites, the planes are in
agreement with the plane around our Galaxy. We find such planes to be common in
our high concentration haloes. The number of co-rotating satellites obtained
from the sign of the line-of-sight velocity shows large variations depending on
the viewing angle and is consistent with that obtained from a sample with
random velocities. We find that the clustering of angular momentum vectors of
the satellites in the plane is a better measure of the kinematic coherence.
Thus we conclude that the line-of- sight velocity is not well suited as a proxy
for the kinematical coherence of the plane. Analysis of the kinematics of our
planes shows a fraction of $\sim$30% chance aligned satellites. Tracking the
satellites in the plane back in time reveals that these planes are a transient
feature and not kinematically coherent as would appear at first sight. Thus we
expect some of the satellites in the plane around Andromeda to have high
velocities perpendicular to the plane.
