Ram pressure stripping and galaxy orbits: The case of the Virgo Cluster

We investigate the role of ram pressure stripping in the Virgo Cluster using N-body simulations. Radial orbits within the Virgo Cluster's gravitational potential are modeled and analyzed with respect to ram pressure stripping. The N-body model consists of 10,000 gas cloud complexes that can have inelastic collisions. Ram pressure is modeled as an additional acceleration on the clouds located at the surface of the gas distribution in the direction of the galaxy's motion within the cluster. We made several simulations, changing the orbital parameters in order to recover different stripping scenarios using realistic temporal ram pressure profiles. We investigate systematically the influence of the inclination angle between the disk and the orbital plane of the galaxy on the gasdynamics. We show that ram pressure can lead to a temporary increase of the central gas surface density. In some cases a considerable part of the total atomic gas mass (several 10(8) M-circle dot) can fall back onto the galactic disk after the stripping event. A quantitative relation between the orbit parameters and the resulting H I deDciency is derived containing explicitly the inclination angle between the disk and the orbital plane. The comparison between existing H I observations and the results of our simulations shows that the H I deficiency depends strongly on galaxy orbits. It is concluded that the scenario in which ram pressure stripping is responsible for the observed H I deficiency is consistent with all H I 21 cm observations in the Virgo Cluster.