A 6% measurement of the Hubble parameter at z∼0.45: direct evidence of the epoch of cosmic re-acceleration

By Michele Moresco, L. Pozzetti, A. Cimatti, Raul Jimenez, C. Maraston, L. Verde, D. Thomas, A. Citro, R. Tojeiro, D. Wilkinson. 2016

1,062 citations recorded by the source corpus.

Deriving the expansion history of the Universe is a major goal of modern cosmology. To date, the most accurate measurements have been obtained with Type Ia Supernovae (SNe) and Baryon Acoustic Oscillations (BAO), providing evidence for the existence of a transition epoch at which the expansion rate changes from decelerated to accelerated. However, these results have been obtained within the framework of specific cosmological models that must be implicitly or explicitly assumed in the measurement. It is therefore crucial to obtain measurements of the accelerated expansion of the Universe independently of assumptions on cosmological models. Here we exploit the unprecedented statistics provided by the Baryon Oscillation Spectroscopic Survey (BOSS, [1-3]) Data Release 9 to provide new constraints on the Hubble parameter H(z) using the cosmic chronometers approach. We extract a sample of more than 130000 of the most massive and passively evolving galaxies, obtaining five new cosmology-independent H(z) measurements in the redshift range 0.3 < z < 0.5, with an accuracy of ∼11–16% incorporating both statistical and systematic errors. Once combined, these measurements yield a 6% accuracy constraint of H(z = 0.4293) = 91.8 ± 5.3 km/s/Mpc. The new data are crucial to provide the first cosmology-independent determination of the transition redshift at high statistical significance, measuring zt = 0.4 ± 0.1, and to significantly disfavor the null hypothesis of no transition between decelerated and accelerated expansion at 99.9% confidence level. This analysis highlights the wide potential of the cosmic chronometers approach: it permits to derive constraints on the expansion history of the Universe with results competitive with standard probes, and most importantly, being the estimates independent of the cosmological model, it can constrain cosmologies beyond—and including—the ΛCDM model.

Subfields: Astronomy and Astrophysics, Instrumentation

View Paper: https://www.semanticscholar.org/paper/bf832274d7bcb0f13ad66fa19e57dc27f4dd7c67

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Citations in the corpus

New observational constraints on f(R) gravity from cosmic chronometers (2016, methodology): “For a detailed description on the implementation of CC data, all possible kind of uncertainties, as well as some related issues, we refer the reader to [77].”
Hubble Parameter and Baryon Acoustic Oscillation Measurement Constraints on the Hubble Constant, the Deviation from the Spatially Flat ΛCDM Model, the Deceleration–Acceleration Transition Redshift, and Spatial Curvature (2017, background): “Moresco et al. (2016), (6).”
Setting the Stage for Cosmic Chronometers. II. Impact of Stellar Population Synthesis Models Systematics and Full Covariance Matrix (2020, methodology): “…resulting slope, i.e., A(D4000n) at a fixed metallicity, with a fifth-order polynomial, A(D4000n) = 5∑ k=0 akD4000 k n (B5) limiting the analysis to the range D4000n > 1.5, as this range matches that spanned by current datasets for CCs (see Moresco et al. 2012b; Moresco 2015; Moresco et al. 2016b).”
HUBBLE PARAMETER MEASUREMENT CONSTRAINTS ON THE REDSHIFT OF THE DECELERATION–ACCELERATION TRANSITION, DYNAMICAL DARK ENERGY, AND SPACE CURVATURE (2016, methodology): “…from non-relativistic matter, and the first measurement of the redshift of this transition (see, e.g., Farooq & Ratra 2013b; Farooq et al. 2013b; Moresco et al. 2016).2 H(z) measurements have also been used to constrain some more conventional cosmological parameters, such as the density of dark…”
Interacting scenarios with dynamical dark energy: Observational constraints and alleviation of the H0 tension (2019, methodology): “• We consider the measurements of the Hubble parameter at various redshifts from the Cosmic Chronometers (CC) [112].”
2020 global reassessment of the neutrino oscillation picture (2020, neutral): “45 [109].”
Interacting dark energy with time varying equation of state and the H0 tension (2018, methodology): “• Hubble parameter measurements from the Cosmic Chronometers (CC) [61].”
Toward a Better Understanding of Cosmic Chronometers: A New Measurement of H(z) at z ∼ 0.7 (2021, methodology): “The latter is orthogonal to the degeneracy that is present in CMB-only data, so that the combination of these two independent probes can eventually provide more stringent constraints on cosmological parameters (see, e.g., Moresco et al. 2016; Vagnozzi et al. 2021a).”
The Cardassian expansion revisited: constraints from updated Hubble parameter measurements and type Ia supernova data (2017, background): “These H(z) points are MNRAS 000, 000–000 (2017) given by different authors as Zhang et al. (2014); Moresco et al. (2012); Moresco (2015); Moresco et al. (2016); Stern et al. (2010), and constitute the majority of our sample (31 points).”