High resolution ALMA observation of the $^{12}$CO(3-2) and 350 GHz
  continuum emissions of the debris disc of 49 Ceti
  We present high resolution ALMA observations of the CO(3-2) and 350 GHz
continuum emissions of the debris disc of 49 Ceti, known to be particularly
rich in molecular gas in spite of its age. The main new results are: i) both CO
and dust discs share a same position angle and a same inclination but the gas
disc is more homogeneous, more central and thinner than the dust disc; ii)
evidence is obtained for a significant deficit of observed CO(3-2) emission at
Doppler velocities differing from the star systemic velocity by less than 1
\kms; iii) gas velocities are accurately measured and found Keplerian over a
broad range of disc radii; iv) the observed CO(3-2) line width is dominated by
Keplerian shear and upper limits are obtained to the intrinsic line width.
Simple phenomenological models of both CO(3-2) and \mbox{350 GHz} continuum
emissions are presented, requiring the use of only very few parameters. The
results are discussed in the frame of currently favoured models.
