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dc.contributor.authorHee, Sonkeen
dc.contributor.authorVázquez, JAen
dc.contributor.authorHandley, Willen
dc.contributor.authorHobson, Michaelen
dc.contributor.authorLasenby, Anthonyen
dc.date.accessioned2017-04-11T14:52:29Z
dc.date.available2017-04-11T14:52:29Z
dc.date.issued2017-04-01en
dc.identifier.issn0035-8711
dc.identifier.urihttps://www.repository.cam.ac.uk/handle/1810/263603
dc.description.abstractData-driven model-independent reconstructions of the dark energy equation of state $w$($z$) are presented using $\textit{Planck}$ 2015 era cosmic microwave background, baryonic acoustic oscillations (BAO), Type Ia supernova (SNIa) and Lyman $\alpha$ (Ly$\alpha$) data. These reconstructions identify the $w$($z$) behaviour supported by the data and show a bifurcation of the equation of state posterior in the range 1.5 < $z$ < 3. Although the concordance $\Lambda$ cold dark matter ($\Lambda$CDM) model is consistent with the data at all redshifts in one of the bifurcated spaces, in the other, a supernegative equation of state (also known as ‘phantom dark energy’) is identified within the 1.5$\sigma$ confidence intervals of the posterior distribution. To identify the power of different data sets in constraining the dark energy equation of state, we use a novel formulation of the Kullback–Leibler divergence. This formalism quantifies the information the data add when moving from priors to posteriors for each possible data set combination. The SNIa and BAO data sets are shown to provide much more constraining power in comparison to the Ly$\alpha$ data sets. Further, SNIa and BAO constrain most strongly around redshift range 0.1–0.5, whilst the Ly$\alpha$ data constrain weakly over a broader range. We do not attribute the supernegative favouring to any particular data set, and note that the $\Lambda$CDM model was favoured at more than 2 log-units in Bayes factors over all the models tested despite the weakly preferred $w$($z$) structure in the data.
dc.description.sponsorshipThis work was performed using the Darwin Supercomputer of the University of Cambridge High Performance Computing Service (http://www.hpc.cam.ac.uk), provided by Dell Inc. using Strategic Research Infrastructure Funding from the Higher Education Funding Council for England and funding from the Science and Technology Facilities Council (STFC). Parts of this work were undertaken on the COSMOS Shared Memory system at DAMTP, University of Cambridge operated on behalf of the STFC DiRAC HPC Facility; this equipment is funded by BIS National E-infrastructure capital grant ST/J005673/1 and STFC grants ST/H008586/1, ST/K00333X/1. SH and WJH thank STFC for fi- nancial support.
dc.language.isoenen
dc.publisherOxford University Press
dc.subjectequation of stateen
dc.subjectmethods: data analysisen
dc.subjectmethods: statisticalen
dc.subjectcosmological parametersen
dc.subjectdark energyen
dc.titleConstraining the dark energy equation of state using Bayes theorem and the Kullback–Leibler divergenceen
dc.typeArticle
prism.endingPage377
prism.issueIdentifier1en
prism.publicationDate2017en
prism.publicationNameMonthly Notices of the Royal Astronomical Societyen
prism.startingPage369
prism.volume466en
dc.identifier.doi10.17863/CAM.8956
dcterms.dateAccepted2016-11-28en
rioxxterms.versionofrecord10.1093/mnras/stw3102en
rioxxterms.versionVoRen
rioxxterms.licenseref.urihttp://www.rioxx.net/licenses/all-rights-reserveden
rioxxterms.licenseref.startdate2017-04-01en
dc.contributor.orcidHandley, Will [0000-0002-5866-0445]
dc.contributor.orcidLasenby, Anthony [0000-0002-8208-6332]
dc.identifier.eissn1365-2966
rioxxterms.typeJournal Article/Reviewen
pubs.funder-project-idSTFC (ST/J005673/1)
pubs.funder-project-idSTFC (ST/K00333X/1)
pubs.funder-project-idSTFC (ST/M00418X/1)
pubs.funder-project-idSTFC (ST/M007065/1)
pubs.funder-project-idSTFC (1208121)
pubs.funder-project-idSTFC (ST/L000636/1)
pubs.funder-project-idSTFC (ST/H008586/1)
pubs.funder-project-idSTFC (ST/P000673/1)
pubs.funder-project-idSTFC (ST/M001172/1)
cam.issuedOnline2016-12-01en
cam.orpheus.successThu Jan 30 12:56:32 GMT 2020 - The item has an open VoR version.*
rioxxterms.freetoread.startdate2100-01-01


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