Masters of Science / One of the main challenges of cosmology is to unveil the nature of dark energy
and dark matter. They can be constrained with baryonic acoustic oscillations
(BAO) and redshift space distortions, amongst others. Both have characteristic
signatures in the dark matter power spectrum. Biased tracers of dark
matter, such as neutral hydrogen, are used to quantify the underlying dark
matter density field. It is generally assumed that on large scales the bias of the
tracer is linear. However, there is a coupling between small and large scales of
the biased tracer which gives rise to a significant non-linear contribution on
linear scales in the power spectrum of the biased tracer. The Hydrogen Intensity
and Real-time eXperiment (HIRAX) will map the brightness temperature
of neutral hydrogen (HI) over BAO scales thanks to the intensity mapping
technique. We forecasted cosmological parameters for HIRAX taking into
account non-linear corrections to the HI power spectrum and compared them
to the linear case. We used methods based on Fisher matrices. We found
values for the bias to error ratio of the cosmological parameters as high as 1
or 7, depending on the noise level. We also investigated the change in peaks
location on the baryonic acoustic oscillations signal. The value of the shift
goes up to Δk = 10-2h/Mpc with a reduction of amplitude of the BAO features
from 16:33% to 0:33%, depending on the scales.
| Identifer | oai:union.ndltd.org:netd.ac.za/oai:union.ndltd.org:uwc/oai:etd.uwc.ac.za:11394/7248 |
| Date | January 2020 |
| Creators | Randrianjanahary, Liantsoa Finaritra |
| Contributors | Santos, Mario |
| 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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