Interactions between galaxies and a hot medium in rich clusters

• Main Author: Kent, Stephen Matthew
• Format: Others
• Language: en
• Published: 1980
• Online Access: https://thesis.library.caltech.edu/3332/1/Kent_s_1980.pdf; Kent, Stephen Matthew (1980) Interactions between galaxies and a hot medium in rich clusters. Dissertation (Ph.D.), California Institute of Technology. doi:10.7907/msvj-7y70. https://resolver.caltech.edu/CaltechETD:etd-09042008-145134 <https://resolver.caltech.edu/CaltechETD:etd-09042008-145134>

The influence of a hot medium on the formation and evolution of galaxies in rich clusters is investigated. Part I begins with an observational study of the two peculiar systems of emission line filaments around the galaxy NGC1275 in the Perseus cluster. It is concluded that one system consists of condensations in an accretion flow from a surrounding medium onto an underlying elliptical galaxy while the second system arises in a superposed but unrelated spiral galaxy. Part II investigates the problem of whether SO galaxies can be formed by the ram pressure sweeping of spirals due to their motion through a hot intracluster medium. It is found that while the ram pressure may do considerable damage to spirals it is too weak by a large factor to produce the required numbers of S0's. In Part III observations of emission lines from spiral galaxies in the x-ray cluster A1367 reveal that they are deficient in gas content relative to field galaxies and this deficiency is strongest for galaxies closest to the region of x-ray emission. This is taken as evidence that spirals can lose a significant fraction of their gas content by interaction with a hot medium and is therefore a manifestation of the considerable damage predicted in Part II. Finally in Part IV the systematic trends in morphological populations observed in clusters are explained as resulting from a truncation of disks in spirals and SO's during their formation due to cluster collapse. Remarkably good agreement is obtained between the predictions of this scenario and a number of observed properties of galaxies in clusters.