Interaction of Galaxies with the ICM

TL;DR

Recent observations and simulations reveal how the intracluster medium (ICM) affects galaxy evolution through processes like ram pressure stripping, leading to HI deficiency, truncated star formation, and morphological changes in cluster galaxies.

Contribution

This paper synthesizes observational data and hydrodynamical simulations to detail the effects of ICM interactions on galaxy gas content and star formation, highlighting new insights into environmental influences.

Findings

HI deficiency extends to 2 Abell radii in cluster galaxies

Ram pressure stripping reproduces observed HI and star formation truncation

Gas-rich galaxies are mainly found in groups before falling into clusters

Abstract

In recent years a wealth of data and detailed hydrodynamical simulations have appeared that show the effects of interactions between the ICM and galaxies. Single dish observations show that cluster galaxies are deficient in their HI content out to 2 Abell radii. The deficient galaxies tend to be on radial orbits. Imaging of the HI distribution in individual galaxies shows a remarkable trend of HI extent with location in the cluster. These trends can be reproduced in simulations of ram pressure stripping by the ICM using SPH and 3D hydro-codes. Detailed imaging of individual galaxies shows in some caes undisturbed old stellar disks, truncated gas disks that are much smaller than the stellar disks, asymmetric extraplanar gas in the center and enhanced central star formation. These phenomena have all been predicted by hydrodynamical simulations. Optical imaging and spectroscopic surveys show that small HI disks go together with truncated star forming disks, that HI deficiency correlates with suppressed star formation rates and that the spatial extent of HI deficiency in clusters is matched by or even surpassed by the extent of reduced star formation rates. Recent volume limited HI imaging surveys of clusters in the local universe show that most gas rich galaxies are located in groups and subclumps, that yet have to fall into the clusters. In these groups we see much evidence for interactions between gas rich galaxies.