Raising the bar: new constraints on the Hubble parameter with cosmic chronometers at z ∼ 2

By Michele Moresco. 2015

902 citations recorded by the source corpus.

One of the most compelling tasks of modern cosmology is to constrain the expansion history of the Universe, since this measurement can give insights on the nature of dark energy and help to estimate cosmological parameters. In this letter are presented two new measurements of the Hubble parameter H(z) obtained with the cosmic chronometer method up to z ∼ 2. Taking advantage of near-infrared spectroscopy of the few very massive and passive galaxies observed at z > 1.4 available in literature, the differential evolution of this population is estimated and calibrated with different stellar population synthesis models to constrain H(z), including in the final error budget all possible sources of systematic uncertainties (star formation history, stellar metallicity, model dependences). This analysis is able to extend significantly the redshift range coverage with respect to present-day constraints, crossing for the first time the limit at z ∼ 1.75. The new H(z) data are used to estimate the gain in accuracy on cosmological parameters with respect to previous measurements in two cosmological models, finding a small but detectable improvement (∼5 per cent) in particular on Ω_M and w_0. Finally, a simulation of a Euclid-like survey has been performed to forecast the expected improvement with future data. The provided constraints have been obtained just with the cosmic chronometers approach, without any additional data, and the results show the high potentiality of this method to constrain the expansion history of the Universe at these redshifts.

Subfields: Astronomy and Astrophysics, Instrumentation

View Paper: https://www.semanticscholar.org/paper/238c55f9e9796d874a9d6d4b5e48be21074e67ef

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Citations in the corpus

Age-dating luminous red galaxies observed with the Southern African Large Telescope (2016, methodology): “…2003; Jimenez et al. 2003; Capozziello et al. 2004; Simon, Verde, & Jimenez 2005; Verkhodanov, Parijskij, & Starobinsky 2005; Dantas et al. 2007; Samushia et al. 2010; Stern et al. 2010; Moresco et al. 2011, 2012; Liu et al. 2012; Zhang et al. 2014; Moresco 2015; Moresco et al. 2016) .”
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HUBBLE PARAMETER MEASUREMENT CONSTRAINTS ON THE REDSHIFT OF THE DECELERATION–ACCELERATION TRANSITION, DYNAMICAL DARK ENERGY, AND SPACE CURVATURE (2016, background): “We have also added two new measurements from Moresco (2015).”
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): “Current H(z) data covers a large redshift range, 0.07 z 2.36 (Simon et al. 2005; Stern et al. 2010; Blake et al. 2012; Moresco et al. 2012; Font-Ribera et al. 2014; Delubac et al. 2015; Moresco 2015; Moresco et al. 2016; Alam et al. 2017), larger than that covered by the Type Ia supernovae.”
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