Litmus tests of the flat ΛCDM model and model-independent measurement of H 0 r d with LSST and DESI

Abstract

In this analysis we apply a model-independent framework to test the flat ΛCDM cosmology using simulated SNIa data from the upcoming Legacy Survey of Space and Time (LSST) and combined with simulated Dark Energy Spectroscopic Instrument (DESI) five-years Baryon Acoustic Oscillations (BAO) data. We adopt an iterative smoothing technique to reconstruct the expansion history from SNIa data, which, when combined with BAO measurements, facilitates a comprehensive test of the Universe's curvature and the nature of dark energy. The analysis is conducted under four different mock fiducial cosmologies: two curvatures (Ωk,0 = 0 and 0.1) and two models of dark energy: a cosmological constant Λ and the phenomenologically emergent dark energy. We forecast that our reconstruction technique can constrain cosmological parameters, such as the curvature (k,0) and c/H0rd, with spread due to the SNIa uncertainties up to ±4% and ±0.1 respectively, without assuming any form of dark energy.