Correlated adiabatic and isocurvature CMB fluctuations in the wake of the WMAP

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dc.creatorValiviita, Jussi
dc.creatorMuhonen, Vesa
dc.date2003-04-10
dc.date2003-10-01
dc.date.accessioned2026-07-07T02:08:13Z
dc.date.available2026-07-07T02:08:13Z
dc.descriptionIn general correlated models, in addition to the usual adiabatic component with a spectral index n_ad1 there is another adiabatic component with a spectral index n_ad2 generated by entropy perturbation during inflation. We extend the analysis of a correlated mixture of adiabatic and isocurvature CMB fluctuations of the WMAP group, who set the two adiabatic spectral indices equal. Allowing n_ad1 and n_ad2 to vary independently we find that the WMAP data favor models where the two adiabatic components have opposite spectral tilts. Using the WMAP data only, the 2-sigma upper bound for the isocurvature fraction f_iso of the initial power spectrum at k_0=0.05 Mpc^{-1} increases somewhat, e.g., from 0.76 of n_ad2 = n_ad1 models to 0.84 with a prior n_iso < 1.84 for the isocurvature spectral index. We also comment on a possible degeneration between the correlation component and the optical depth tau. Moreover, the measured low quadrupole in the TT angular power could be achieved by a strong negative correlation, but then one needs a large tau to fit the TE spectrum.
dc.description5 pages, 7 figures. V2: Added 2 figures and revised a bit the results section. This is a slightly longer version than the published one in PRL
dc.identifierhttps://arxiv.org/abs/astro-ph/0304175
dc.identifierhttp://arxiv.org/abs/astro-ph/0304175
dc.identifierPhys.Rev.Lett. 91 (2003) 131302
dc.identifierdoi:10.1103/PhysRevLett.91.131302
dc.identifier.urihttp://salesiana.dossiersoluciones.com/handle/123456789/5957
dc.subjectAstrophysics
dc.subjectHigh Energy Physics - Phenomenology
dc.titleCorrelated adiabatic and isocurvature CMB fluctuations in the wake of the WMAP
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