CMB Tensions with Low-Redshift H0 and S8 Measurements: Impact of a Redshift-Dependent Type-Ia Supernovae Intrinsic Luminosity

Abstract

With the recent increase in precision of our cosmological datasets, measurements of ΛCDM 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, H 0 , and the weighted amplitude of matter fluctuations, S 8 , 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. We consider a SNIa intrinsic luminosity dependence on redshift due to the star formation rate in its environment, or the metallicity of the progenitor. We find that the H 0 and S 8 tensions can be significantly alleviated, or even removed, if we account for varying Dark Energy for SNIa and CMB data. However, the tensions remain when we add baryon acoustic oscillations (BAO) data into the analysis, even after the addition of extra SNIa systematic uncertainties. This points towards the need of either new physics beyond late-time Dark Energy, or other unaccounted systematic effects (particulary in BAO measurements), to fully solve the present tensions.

Determining the range of validity of quasar X-ray and UV flux measurements for constraining cosmological model parameters

“…Other local expansion rate determinations have slightly lower central values with slightly larger error bars(Rigault et al 2015;Zhang et al 2017;Dhawan et al 2017;Fernández Arenas et al 2018;Freedman et al 2020;Rameez & Sarkar 2019;Breuval et al 2020;Efstathiou 2020;Khetan et al 2020). Our 𝐻 0 measurements are consistent with earlier median statistics estimates(Gott et al 2001;Chen & Ratra 2003b) and a number of recent measurements(Chen et al 2017; DES Collaboration 2018;Gómez-Valent & Amendola 2018; Planck Collaboration 2020;Zhang 2018;Domínguez et al 2019;Martinelli & Tutusaus 2019;Cuceu et al 2019;Zeng & Yan 2019;Schöneberg et al 2019;Lin & Ishak 2019;Blum et al 2020;Lyu et al 2020;Philcox et al. 2020; Zhang & Huang 2020; Birrer et al 2020; Denzel et al 2020; Pogosian et al 2020; Boruah et al 2020; Kim et al 2020).…”

Dark Energy with Phantom Crossing and the H0 Tension

“…There are many attempts to alleviate the issue in the literature (see for an incomplete list of works Refs. [ 36 , 37 , 38 , 39 , 40 , 41 , 42 , 43 , 44 , 45 , 46 , 47 , 48 , 49 , 50 , 51 , 52 , 53 , 54 , 55 , 56 , 57 , 58 , 59 , 60 , 61 , 62 , 63 , 64 , 65 , 66 , 67 , 68 , 69 , 70 , 71 , 72 , 73 , 74 , 75 , 76 , 77 , 78 ] and the recent overview in [ 79 , 80 ]). It has been recently discussed [ 81 , 82 ] that a transition in absolute magnitude for SnIa can also explain the apparent tension between the local and CMB measurements of the Hubble parameter .…”

Latest evidence for a late time vacuum–geodesic CDM interaction

“…We also note that, due to the coupling between the vacuum and cold dark matter in this scenario, RSD do not directly constrain the growth factor f as they do in ΛCDM [46,47]. Instead, the RSD constrain what we denote as the interaction growth factor, f i ,…”

“…If BAO are used in combination with supernovae catalogues then late time solutions become disfavoured, and interacting dark energy models will therefore struggle to resolve the tension (see e.g. [45,46]). However, this reasoning does not justify the exclusion of these datasets from model constraining analysis and we therefore make a point of including multiple BAO measurements in this work.…”