Wakes and the dynamics of galaxy clusters
Wakes and the dynamics of galaxy clusters
This thesis investigates the interaction of gaseous media in gravitationally-bound groups and clusters of galaxies; in particular, X-ray data are examined for the presence of 'wakes' of material created by the movement of galaxies within clusters.
Theoretical models assume galactic wakes to be formed by one of two principal mechanisms: either the interstellar medium (ISM) of a galaxy is stripped by the ram pressure of the surrounding intracluster medium (ICM), causing X-ray-emitting material to trail out behind the galaxy; or the mass of the galaxy causes ICM gas to be accreted into a Bondi-Hoyle accretion wake. The effect of environment upon the physical characteristics of wakes is a key question explored in this thesis.
A statistical, objective method is developed to search for wakes. The first systematic search for wakes in a cluster is made using data on the nearby, richness class 0 cluster Abell 160, acquired using the ROSAT satellite. This work reveals that a significant population of cluster galaxies appear to be associated with wake-like features; the most probable wake detections imply that their parent galaxies are on inward-bound orbits. A 'radial bias' model is proposed to explain this observation, noting that galaxies moving on elliptical orbits will spend a greater time away from the cluster centre than near it, and hence will be able to enhance their ISM through internal astrophysical processes, before having this material stripped as they fall towards the centre. Once past the centre, however, wakes cannot be formed through ram pressure stripping as the galaxies have not had time to replenish their gaseous content, and hence the brightest wakes are likely to be those accompanying galaxies on inward-radial orbits.
University of Southampton
Drake, Nick
825cef91-08e8-4533-afd1-992c1738e828
2000
Drake, Nick
825cef91-08e8-4533-afd1-992c1738e828
Drake, Nick
(2000)
Wakes and the dynamics of galaxy clusters.
University of Southampton, Doctoral Thesis.
Record type:
Thesis
(Doctoral)
Abstract
This thesis investigates the interaction of gaseous media in gravitationally-bound groups and clusters of galaxies; in particular, X-ray data are examined for the presence of 'wakes' of material created by the movement of galaxies within clusters.
Theoretical models assume galactic wakes to be formed by one of two principal mechanisms: either the interstellar medium (ISM) of a galaxy is stripped by the ram pressure of the surrounding intracluster medium (ICM), causing X-ray-emitting material to trail out behind the galaxy; or the mass of the galaxy causes ICM gas to be accreted into a Bondi-Hoyle accretion wake. The effect of environment upon the physical characteristics of wakes is a key question explored in this thesis.
A statistical, objective method is developed to search for wakes. The first systematic search for wakes in a cluster is made using data on the nearby, richness class 0 cluster Abell 160, acquired using the ROSAT satellite. This work reveals that a significant population of cluster galaxies appear to be associated with wake-like features; the most probable wake detections imply that their parent galaxies are on inward-bound orbits. A 'radial bias' model is proposed to explain this observation, noting that galaxies moving on elliptical orbits will spend a greater time away from the cluster centre than near it, and hence will be able to enhance their ISM through internal astrophysical processes, before having this material stripped as they fall towards the centre. Once past the centre, however, wakes cannot be formed through ram pressure stripping as the galaxies have not had time to replenish their gaseous content, and hence the brightest wakes are likely to be those accompanying galaxies on inward-radial orbits.
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Published date: 2000
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Local EPrints ID: 464160
URI: http://eprints.soton.ac.uk/id/eprint/464160
PURE UUID: aea2a8b0-3081-4383-a4a6-ffe57f34b91c
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Date deposited: 04 Jul 2022 21:21
Last modified: 16 Mar 2024 19:18
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Author:
Nick Drake
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