Ram pressure drag - the effects of ram pressure on dark matter and stellar disk dynamics

TL;DR

This paper explores how ram pressure stripping in galaxy clusters affects the dynamics of stellar disks and dark matter, showing that gas removal can cause disk thickening and displacement of the galaxy's core.

Contribution

It provides a simple analytical model describing how ram pressure drag influences stellar and dark matter components in gas-rich disk galaxies.

Findings

Ram pressure stripping can displace stellar disks and dark matter cores by several kiloparsecs.

Gas removal leads to significant disk thickening, approximately doubling the thickness.

The drag force depends on ram pressure and galaxy properties, affecting galaxy morphology.

Abstract

We investigate the effects of ram pressure stripping on gas-rich disk galaxies in the cluster environment. Ram pressure stripping principally effects the atomic gas in disk galaxies, stripping away outer disk gas to a truncation radius. We demonstrate that the drag force exerted on truncated gas disks is passed to the stellar disk, and surrounding dark matter through their mutual gravity. Using a toy model of ram pressure stripping, we show that this can drag a stellar disk and dark matter cusp off centre within it's 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 disk galaxy properties to first order. The motion of the disk can result in temporary deformation of the stellar disk. However we demonstrate that the key source of stellar disk heating is the removal of the gas potential from within the disk. This can result in disk thickening by approximately a factor of two in gas-rich disks.