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Keywords:

  • methods: numerical;
  • galaxies: clusters: general;
  • galaxies: evolution;
  • intergalactic medium;
  • galaxies: kinematics and dynamics

ABSTRACT

We investigate the effects of ram pressure stripping on gas-rich disc galaxies in the cluster environment. Ram pressure stripping principally affects the atomic gas in disc galaxies, stripping away outer disc gas to a truncation radius. We demonstrate that the drag force exerted on truncated gas discs is passed to the stellar disc, and surrounding dark matter through their mutual gravity. Using a toy model of ram pressure stripping, we show that this can drag a stellar disc and dark matter cusp off centre within its dark matter halo by several kiloparsecs. We present a simple analytical description of this process that predicts the drag force strength and its dependency on ram pressures and disc galaxy properties to first order. The motion of the disc can result in temporary deformation of the stellar disc. However, we demonstrate that the key source of stellar disc heating is the removal of the gas potential from within the disc. This can result in disc thickening by approximately a factor of 2 in gas-rich discs.