S S symmetry Article CMB Tensions with Low-Redshift H0 and S8 Measurements: Impact of a Redshift-Dependent Type-Ia Supernovae Intrinsic Luminosity Matteo Martinelli 1,* and Isaac Tutusaus 2,3,4,* 1 Institute Lorentz, Leiden University, PO Box 9506, 2300 RA Leiden, The Netherlands 2 Institute of Space Sciences (ICE, CSIC), Campus UAB, Carrer de Can Magrans, s/n, 08193 Barcelona, Spain 3 Institut d’Estudis Espacials de Catalunya (IEEC), Carrer Gran Capità 2-4, 08193 Barcelona, Spain 4 CNRS, IRAP, UPS-OMP, Université de Toulouse, 14 Avenue Edouard Belin, F-31400 Toulouse, France * Correspondence:
[email protected] (M.M.);
[email protected] (I.T.) Received: 28 June 2019; Accepted: 24 July 2019; Published: 2 August 2019 Abstract: With the recent increase in precision of our cosmological datasets, measurements of LCDM model parameter provided by high- and low-redshift observations started to be in tension, i.e., the obtained values of such parameters were shown to be significantly different in a statistical sense. In this work we tackle the tension on the value of the Hubble parameter, H0, and the weighted amplitude of matter fluctuations, S8, obtained from local or low-redshift measurements and from cosmic microwave background (CMB) observations. We combine the main approaches previously used in the literature by extending the cosmological model and accounting for extra systematic uncertainties. With such analysis we aim at exploring non standard cosmological models, implying deviation from a cosmological constant driven acceleration of the Universe expansion, in the presence of additional uncertainties in measurements. In more detail, we reconstruct the Dark Energy equation of state as a function of redshift, while we study the impact of type-Ia supernovae (SNIa) redshift-dependent astrophysical systematic effects on these tensions.