Implications of a transition in the dark energy equation of state for the H0 and σ8 tensions
Abstract
We explore the implications of a rapid appearance of dark energy between the redshifts (z) of one and two on the expansion rate and growth of perturbations. Using both Gaussian process regression and a parametric model, we show that this is the preferred solution to the current set of low-redshift (z<3) distance measurements if H0=73 km s-1 Mpc-1 to within 1% and the high-redshift expansion history is unchanged from the ΛCDM inference by the Planck satellite. Dark energy was effectively non-existent around z=2, but its density is close to the ΛCDM model value today, with an equation of state greater than -1 at z<0.5. If sources of clustering other than matter are negligible, we show that this expansion history leads to slower growth of perturbations at z<1, compared to ΛCDM, that is measurable by upcoming surveys and can alleviate the σ8 tension between the Planck CMB temperature and low-redshift probes of the large-scale structure.
- Publication:
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Journal of Cosmology and Astroparticle Physics
- Pub Date:
- December 2019
- DOI:
- 10.1088/1475-7516/2019/12/035
- arXiv:
- arXiv:1905.10198
- Bibcode:
- 2019JCAP...12..035K
- Keywords:
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- Astrophysics - Cosmology and Nongalactic Astrophysics
- E-Print:
- 24 pages, 16 figures