>Magister Scientiae - MSc / The growth rate of large-scale structure is a key probe of gravity in the accelerating
Universe. Standard models of Dark Energy within General Relativity predict essentially
the same growth rate, whereas Modified Gravity theories without Dark Energy predict
a different growth rate. Redshift-space distortions lead to anisotropy in the power
spectrum, and extracting the monopole and quadrupole allows us to determine the
growth rate and thus test theories of gravity. We investigate redshift-space distortions
in the intensity maps of the 21cm emission line of neutral hydrogen (HI) in galaxies
after the Epoch of Reionization: HI intensity mapping delivers very accurate redshifts.
We first use the standard approach based on the Fourier power spectrum. Then we
explored an alternative approach, based on the spherical-harmonic angular power
spectrum. Fisher forecasting was used to make predictions of the accuracy with which
MeerKAT will measure the growth rate parameter, via the proposed MeerKAT Large
Area Synoptic Survey (MeerKLASS). Then we extend the forecasts to consider the
planned HI intensity mapping survey in Phase 1 of the Square Kilometre Array. These
forecasts enable us to predict at what level of accuracy General relativity and various
alternative theories could be ruled out.
| Identifer | oai:union.ndltd.org:netd.ac.za/oai:union.ndltd.org:uwc/oai:etd.uwc.ac.za:11394/6793 |
| Date | January 2019 |
| Creators | Viljoen, Jan-Albert |
| Contributors | Maartens, Roy, Fonseca, José |
| 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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