We present a new deep 21-cm survey of the Andromeda galaxy , based on high resolution observations performed with the Synthesis Telescope and the 26-m antenna at DRAO .
The H i distribution and kinematics of the disc are analyzed and basic dynamical properties are given .
The rotation curve is measured out to 38 kpc , showing a nuclear peak at 340 km s ^ { -1 } , a dip at 202 km s ^ { -1 } around 4 kpc , two distinct flat parts at 264 km s ^ { -1 } and 230 km s ^ { -1 } and an increase to 275 km s ^ { -1 } in the outermost regions .
Except for the innermost regions , the axisymmetry of the gas rotation is very good .
A very strong warp of the H i disc is evidenced .
The central regions appear less inclined than the average disc inclination of 74° , while the outer regions appear more inclined .
Mass distribution models by \Lambda CDM Navarro-Frenk-White , Einasto or pseudo-isothermal dark matter halos with baryonic components are presented .
They fail to reproduce the exact shape of the rotation curve .
No significant differences are measured between the various shapes of halo .
The dynamical mass of M31 enclosed within a radius of 38 kpc is ( 4.7 \pm 0.5 ) \times 10 ^ { 11 } { \cal M } _ { \odot } .
The dark matter component is almost 4 times more massive than the baryonic mass inside this radius .
A total mass of 1.0 \times 10 ^ { 12 } { \cal M } _ { \odot } is derived inside the virial radius .
New H i structures are discovered in the datacube , like the detection of up to five H i components per spectrum , which is very rarely seen in other galaxies .
The most remarkable new H i structures are thin H i spurs and an external arm in the disc outskirts .
A relationship between these spurs and outer stellar clumps is evidenced .
The external arm is 32 kpc long , lies on the far side of the galaxy and has no obvious counterpart on the other side of the galaxy .
Its kinematics clearly differs from the outer adjacent disc .
Both these H i perturbations could result from tidal interactions with galaxy companions .