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dc.contributor.authorTsagas, Christos G
dc.date.accessioned2022-06-11T15:00:40Z
dc.date.available2022-06-11T15:00:40Z
dc.date.issued2022-06
dc.date.submitted2021-12-08
dc.identifier.issn1434-6044
dc.identifier.others10052-022-10452-4
dc.identifier.other10452
dc.identifier.urihttps://www.repository.cam.ac.uk/handle/1810/338021
dc.description.abstract<jats:title>Abstract</jats:title><jats:p>Large-scale bulk peculiar motions introduce a characteristic length scale, inside which the local kinematics are dominated by peculiar-velocity perturbations rather than by the background Hubble expansion. Regions smaller than the aforementioned critical length, which typically varies between few hundred and several hundred Mpc, can be heavily “contaminated” by the observers’ relative motion. For example, at the critical length – hereafter referred to as the “transition scale”, the sign of the locally measured deceleration parameter can change from positive to negative, while the surrounding universe is still decelerating globally. Overall, distant observers can assign very different values to their local deceleration parameters, entirely because of their relative motion. In practice, this suggests that information selected from regions inside and close to the transition scale hold only locally and they should not be readily extrapolated to the global universe. We show that this principle applies to essentially all Friedmann backgrounds, irrespective of their equation of state and spatial curvature. Put another way, the transition scale and the related effects are generic to linear peculiar-velocity perturbations. This study generalises previous work applied, primarily for reasons of mathematical simplicity, to a perturbed Einstein–de Sitter universe.</jats:p>
dc.languageen
dc.publisherSpringer Science and Business Media LLC
dc.subjectRegular Article - Theoretical Physics
dc.titleThe deceleration parameter in ‘tilted’ universes: generalising the Friedmann background
dc.typeArticle
dc.date.updated2022-06-11T15:00:39Z
prism.issueIdentifier6
prism.publicationNameThe European Physical Journal C
prism.volume82
dc.identifier.doi10.17863/CAM.85426
dcterms.dateAccepted2022-05-22
rioxxterms.versionofrecord10.1140/epjc/s10052-022-10452-4
rioxxterms.versionVoR
rioxxterms.licenseref.urihttp://creativecommons.org/licenses/by/4.0/
dc.identifier.eissn1434-6052
pubs.funder-project-idHellenic Foundation for Research and Innovation (789)
cam.issuedOnline2022-06-10


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