Does quartessence ease cosmic tensions?

Publication date: Available online 29 November 2018Source: Physics of the Dark UniverseAuthor(s): Stefano Camera, Matteo Martinelli, Daniele BertaccaAbstractTensions between cosmic microwave background observations and the growth of the large-scale structure inferred from late-time probes pose a serious challenge to the concordance ΛCDM cosmological model. State-of-the-art data from the Planck satellite predicts a higher rate of structure growth than what preferred by low-redshift observables. Such tension has hitherto eluded conclusive explanations in terms of straightforward modifications to ΛCDM, e.g. the inclusion of massive neutrinos or a dynamical dark energy component. Here, we investigate models of ‘quartessence’—a single dark component mimicking both dark matter and dark energy—whose non-vanishing sound speed inhibits structure growth at late times on scales smaller than its corresponding Jeans’ length. In principle, this could reconcile high- and low-redshift observations. We put this hypothesis to test against temperature and polarisation spectra from the latest Planck release, SDSS DR12 measurements of baryon acoustic oscillations and redshift-space distortions, and cosmic shear correlation functions from KiDS. This the first time that any specific model of quartessence is applied to actual data. We show that, if we naïvely apply ΛCDM nonlinear prescription to quartessence, the combined data sets allow for tight constraints on the model paramete...
Source: Physics of the Dark Universe - Category: Physics Source Type: research
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