Harmonic analysis of the Ha velocity field of NGC 4254
  The ionized gas kinematics of the Virgo Cluster galaxy NGC 4254 (Messier 99) is analyzed by an harmonic decomposition of the velocity field into Fourier coefficients. The aims of this study are to measure the kinematical asymmetries of Virgo cluster galaxies and to connect them to the environment. The analysis reveals significant $m=1,2,4$ terms which origins are discussed. 
Laurent Chemin, Olivier Hernandez, Chantal Balkowski, Claude Carignan,   Philippe Amram