Evidence of a bisymmetric spiral in the Milky Way
  Context: Because of our viewing point within the Galactic disc, it is
extremely difficult to observe the spiral structure of the Milky Way.
  Aims: To clarify the structure of the Galaxy by re-examination of gas
distributions and data from 2MASS; to determine stream memberships among local
stars and to show the relationship between streaming motions and spiral
structure.
  Methods: We extend the spiral pattern found from neutral gas towards the
Galactic centre using data from 2MASS. We select a population of 23 075 local
disc stars for which complete kinematic data is available. We plot eccentricity
against the true anomaly for stellar orbits and identify streams as dense
regions of the plot. We reconstruct the spiral pattern by replacing each star
at a random position of the inward part of its orbit.
  Results: We find evidence in 2MASS of a bar of length 4.2 \pm 0.1 kpc at
angle 30 \pm 10\degree. We extend spiral structure by more than a full turn
toward the Galactic centre, and confirm that the Milky Way is a two-armed
grand-design bisymmetric spiral with pitch angle 5.56 \pm 0.06\degree.
Memberships of kinematic groups are assigned to 98% of local disc stars and it
is seen that the large majority of local stars have orbits aligned with this
spiral structure.
