When Did Cosmic Acceleration Start ?

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dc.creatorMelchiorri, Alessandro
dc.creatorPagano, Luca
dc.creatorPandolfi, Stefania
dc.date2007-06-10
dc.date.accessioned2026-07-07T12:13:33Z
dc.date.available2026-07-07T12:13:33Z
dc.descriptionA precise determination, and comparison, of the epoch of the onset of cosmic acceleration, at redshift z_acc, and of dark energy domination, at z_eq, provides an interesting measure with which to parameterize dark energy models. By combining several cosmological datasets we place constraints on the redshift and age of cosmological acceleration. For a Lambda-CDM model, we find the constraint z_acc=0.76\pm0.10 at 95% c.l., occurring 6.7\pm0.4 Gyrs ago. Allowing a constant equation of state but different from -1 changes the constraints to z_acc=0.81\pm0.12 (6.9\pm0.5 Gyrs ago) and z_eq=0.48\pm0.14(4.9\pm0.9 Gyrs ago), while dynamical models markedly increase the error on the constraints with z_acc=0.81\pm0.30 (6.8\pm1.4 Gyrs ago) and z_eq=0.44\pm0.20 (4.5\pm1.0 Gyrs ago). Unified dark energy models as Silent Quartessence yield: z_acc=0.80\pm0.16 (6.8\pm0.6 Gyrs ago).
dc.description5 pages, 2 figures
dc.identifierhttps://arxiv.org/abs/0706.1314
dc.identifierhttp://arxiv.org/abs/0706.1314
dc.identifierPhys.Rev.D76:041301,2007
dc.identifierdoi:10.1103/PhysRevD.76.041301
dc.identifier.urihttp://salesiana.dossiersoluciones.com/handle/123456789/210884
dc.subjectAstrophysics
dc.subjectGeneral Relativity and Quantum Cosmology
dc.subjectHigh Energy Physics - Phenomenology
dc.titleWhen Did Cosmic Acceleration Start ?
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