Philosophiae Doctor - PhD / Numerical simulations play a crucial role in testing current cosmological models of
the formation and evolution of the cosmic structure observed in the modern Universe.
Simulations of the collapse of both baryonic and non-baryonic matter under
the influence of gravity have yielded important results in our understanding of the
large scale structure of the Universe. In addition to the underlying large scale structure,
simulations which include gas dynamics can give us valuable insight into, and
allow us to make testable predictions on, the nature and distribution of baryonic
matter on a wide range of scales.
In this work we give an overview of cosmological simulations and the methods
employed in the solution of many body problems. We then present three projects
focusing on scales ranging from individual galaxies to the cosmic web connecting
clusters of galaxies thereby demonstrating the potential and diversity of numerical
simulations in the fields of cosmology and astrophysics.
We firstly investigate the environmental dependance of neutral hydrogen in the
intergalactic medium by utilising high resolution cosmological hydrodynamic simulations in Chapter 3. We find that the extent of the neutral hydrogen radial profile
is dependant on both the environment of the galaxy and its classification within the
group ie. whether it is a central or satellite galaxy. We investigate whether this
effect could arise from ram pressure forces exerted on the galaxies and find good
agreement between galaxies experiencing high ram pressure forces and those with a
low neutral hydrogen content.
In Chapter 4 we investigate the velocity–shape alignment of clusters in a dark
matter only simulation and the effect of such an alignment on measurements of the
kinetic Sunyaev–Zeldovich (kSZ) effect. We find an alignment not only exists but
can lead to an enhancement in the kSZ signal of up to 60% when the cluster is
orientated along the line-of-sight.
Finally we attempt to identify shocked gas in clusters and filaments using intermediate
resolution cosmological hydrodynamic simulations in Chapter 5 with a
view to predicting the synchrotron emission from these areas, something that may
be detectable with the Square Kilometer Array.
| Identifer | oai:union.ndltd.org:netd.ac.za/oai:union.ndltd.org:uwc/oai:etd.uwc.ac.za:11394/4042 |
| Date | January 2013 |
| Creators | Cunnama, Daniel |
| Publisher | University of the Western Cape |
| Source Sets | South African National ETD Portal |
| Language | English |
| Detected Language | English |
| Rights | University of the Western Cape |
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