Deep wide field HI imaging of Messier 31
  We report on preliminary results from a new deep 21-cm survey of the
Andromeda galaxy, based on observations performed with the Synthesis Telescope
and the 26-m antenna at DRAO. The HI distribution and kinematics of the disc
are analyzed and basic dynamical properties are derived. New HI structures are
discovered, like thin HI spur-like structures and an external arm in the disc
outskirts. The HI spurs are related to perturbed stellar clumps outside the
main disc of M31. The external arm lies on the far, receding side of the galaxy
and has no obvious counterpart in the opposite side. These HI perturbations
probably result from tidal interactions with companions. It is found a
dynamical mass of 4.7 +/- 0.5 x10^11 Msol enclosed within a radius R = 38 kpc
and a total mass of ~1 x10^12 Msol inside the virial radius.
