Hints of Isocurvature Perturbations in the Cosmic Microwave Background?

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dc.creatorKeskitalo, Reijo
dc.creatorKurki-Suonio, Hannu
dc.creatorMuhonen, Vesa
dc.creatorValiviita, Jussi
dc.date2006-11-30
dc.date2007-09-19
dc.date.accessioned2026-07-07T11:00:19Z
dc.date.available2026-07-07T11:00:19Z
dc.descriptionThe improved data on the cosmic microwave background (CMB) anisotropy allow a better determination of the adiabaticity of the primordial perturbation. Interestingly, we find that recent CMB data seem to favor a contribution of a primordial isocurvature mode where the entropy perturbation is positively correlated with the primordial curvature perturbation and has a large spectral index (niso ~ 3). With 4 additional parameters we obtain a better fit to the CMB data by Delta chi^2 = 9.7 compared to an adiabatic model. For this best-fit model the nonadiabatic contribution to the CMB temperature variance is 4%. According to a Markov Chain Monte Carlo analysis the nonadiabatic contribution is positive at more than 95% C.L. The exact C.L. depends somewhat on the choice of priors, and we discuss the effect of different priors as well as additional cosmological data.
dc.descriptionv1&2: 4 pages, 2 figures. v4: 16 pages, 7 figures, iopart style. Revised the 'Other cosmological data' section, added a detailed discussion on the effect of priors, and added many figures. Published version
dc.identifierhttps://arxiv.org/abs/astro-ph/0611917
dc.identifierhttp://arxiv.org/abs/astro-ph/0611917
dc.identifierJCAP0709:008,2007
dc.identifierdoi:10.1088/1475-7516/2007/09/008
dc.identifier.urihttp://salesiana.dossiersoluciones.com/handle/123456789/187655
dc.subjectAstrophysics
dc.subjectHigh Energy Physics - Phenomenology
dc.titleHints of Isocurvature Perturbations in the Cosmic Microwave Background?
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