| 1. |
- Bacon, David J., et al.
(författare)
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Cosmology with Phase 1 of the Square Kilometre Array Red Book 2018 : Technical specifications and performance forecasts
- 2020
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Ingår i: Publications Astronomical Society of Australia. - : Cambridge University Press (CUP). - 1323-3580 .- 1448-6083. ; 37
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Tidskriftsartikel (refereegranskat)abstract
- We present a detailed overview of the cosmological surveys that we aim to carry out with Phase 1 of the Square Kilometre Array (SKA1) and the science that they will enable. We highlight three main surveys: a medium-deep continuum weak lensing and low-redshift spectroscopic HI galaxy survey over 5 000 deg2; a wide and deep continuum galaxy and HI intensity mapping (IM) survey over 20 000 deg2 from z = 0.35 to 3; and a deep, high-redshift HI IM survey over 100 deg2 from z = 3 to 6. Taken together, these surveys will achieve an array of important scientific goals: measuring the equation of state of dark energy out to z = 3 with percent-level precision measurements of the cosmic expansion rate; constraining possible deviations from General Relativity on cosmological scales by measuring the growth rate of structure through multiple independent methods; mapping the structure of the Universe on the largest accessible scales, thus constraining fundamental properties such as isotropy, homogeneity, and non-Gaussianity; and measuring the HI density and bias out to z = 6. These surveys will also provide highly complementary clustering and weak lensing measurements that have independent systematic uncertainties to those of optical and near-infrared (NIR) surveys like Euclid, LSST, and WFIRST leading to a multitude of synergies that can improve constraints significantly beyond what optical or radio surveys can achieve on their own. This document, the 2018 Red Book, provides reference technical specifications, cosmological parameter forecasts, and an overview of relevant systematic effects for the three key surveys and will be regularly updated by the Cosmology Science Working Group in the run up to start of operations and the Key Science Programme of SKA1.
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| 2. |
- Tsaprazi, Eleni, 1996-
(författare)
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Physics-informed inferences of galaxy clustering with Bayesian forward modelling
- 2023
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Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- In this thesis, we showcase four novel approaches to constraining the relationship between cosmological observables and the large-scale structure. The majority of the energy content of the Universe in the concordance cosmological model remains largely unknown. Galaxy clustering can constrain the physical mechanism that links galaxy observations to structure formation. Traditional approaches to constraining this relation either rely on summary statistics of galaxy clustering, which lead to information loss or on ad-hoc assumptions, which can bias cosmological conclusions if accounted for improperly. The frameworks presented here ensure the self-consistent propagation of modelled observational uncertainties and extraction of high-order statistics from galaxy clustering. In Paper I, we investigate the potential of supernovae as large-scale structure probes, complementary to galaxy clustering for multi-tracer cosmology. If supernovae are biased relative to galaxies, their combination can improve the mapping of the large-scale structure. We find that supernovae cluster similarly to galaxies at 3.9 Mpc through cross-correlation of supernova locations with the gravitational tidal shear. In the second study, we generate supernova simulations informed about galaxy clustering, galaxy formation and evolution. We model supernova rates from the simulated star-formation histories and estimate the supernova bias with respect to the galaxy density field. We find that supernovae are less clustered than galaxies. The relative biasing signal was obscured in Paper I due to shot noise. In Paper II, we constrain galaxy intrinsic alignment -- a systematic effect in weak gravitational lensing and a probe of galaxy formation and evolution -- accounting for all high-order statistics and nonlinear structure growth down to 15.6 Mpc/h. We report a 4σ detection of galaxy intrinsic alignment, constant with luminosity, color and redshift at 20 Mpc/h. In Paper III, we present a framework to jointly constrain the large-scale structure and photometric galaxy clustering. Our approach is the first to infer the entire structure formation history and the filamentary pattern of the dark matter distribution, despite the large redshift uncertainties. Our approach guarantees the improvement of arbitrarily large photometric redshift uncertainties through galaxy clustering.
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