Whilst the underlying assumption of the Friedman-Lemaître-Robertson-Walker (FLRW) cosmological model is that matter is homogeneously distributed throughout the universe, gravitational influences over the life of the universe have resulted in mass clustered on a range of scales. Hence we expect that, in our inhomogeneous Universe, the view of an observer will be influenced by the location and local environment. Here, we analyse the one-point probability distribution functions and angular power spectra of weak-lensing (WL) convergence and magnification numerically to investigate the influence of our local environment on WL statistics in relativistic N-body simulations. To achieve this, we numerically solve the null geodesic equations which describe the propagation of light bundles backwards in time from today, and develop a ray-tracing algorithm, and from these calculate various WL properties. Our findings demonstrate how cosmological observations of large-scale structure through WL can be impacted by the locality of the observer. We also calculate the constraints on the cosmological parameters as a function of redshift from the theoretical and numerical study of the angular power spectrum of WL convergence. This study concludes the minimal redshift for the constraint on the parameter Ω_m (H₀) is 𝓏 ∼ 0.2 (⁠𝓏 ∼ 0.6) beyond which the local environment’s effect is negligible and the data from WL surveys are more meaningful above that redshift. The outcomes of this study will have direct consequences for future surveys, where per cent-level-precision is necessary.

Item Type:	Refereed Article
Keywords:	gravitational lensing: weak – methods: numerical – dark matter – large-scale structure of Universe
Research Division:	Physical Sciences
Research Group:	Astronomical sciences
Research Field:	Cosmology and extragalactic astronomy
Objective Division:	Expanding Knowledge
Objective Group:	Expanding knowledge
Objective Field:	Expanding knowledge in the physical sciences
UTAS Author:	Bolejko, K (Dr Krzysztof Bolejko)
ID Code:	148272
Year Published:	2021
Funding Support:	Australian Research Council (FT140101270)
Web of Science® Times Cited:	2
Deposited By:	Physics
Deposited On:	2021-12-15
Last Modified:	2022-02-24
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