Browsing by Author "Baatjes Ron Ryan"

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    Multipoles of the redshift-space power spectrum from SKAO and other surveys
    (University of the Western Cape, 2025) Baatjes Ron Ryan
    The large-scale distribution of neutral hydrogen in the late universe provides a probe of the underlying distribution of matter, which is a powerful complement to the standard probe delivered by galaxy number counts. Measuring the neutral hydrogen distribution with MeerKAT, SKAO and other radio telescopes through the hydrogen 21 cm line emission has the potential to become a key cosmological probe in the coming years. We investigate the cosmological constraining power of the 21 cm intensity mapping power spectrum in redshift space. To this end, we decompose the power spectrum into multipoles, modelling the effects of foreground avoidance, telescope beam, instrumental noise and the bias of 21 cm intensity fluctuations. Then we use Fisher forecasting methods to estimate the precision that is obtainable by proposed surveys and on the full SKAO. Measurements of the power spectrum multipoles enable measurements of key cosmological parameters and we estimate the precision of such measurements. In particular, the multipoles provide an estimate of the growth rate of large-scale structure, which can deliver tests of the theory of gravity.