Generalized Lemaitre-Tolman-Bondi model with inhomogeneous isotropic dark energy: Observational constraints
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Grande, J.
Perivolaropoulos, L.
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peer reviewed
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Physical Review D
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We consider on-center and off-center observers in an inhomogeneous, spherically symmetric, isocurvature (flat) concentration of dark energy with a typical size of a few Gpc. Such a concentration could be produced e. g. by a recently formed global monopole with core size that approaches the Hubble scale. In this case we would have what may be called "topological quintessence" in analogy with the well-known topological inflation. We show that the minimum comoving radius r(0) (min) of such a dark energy inhomogeneity that is consistent with the Union2 type Ia supernovae data at the 3 sigma level is r(0) (min) similar or equal to 1: 8 Gpc. As expected, the best-fit fractional dark energy density at the center, Omega(X,in), approaches the corresponding Lambda CDM value Omega(X,in) = 0.73 for large enough values of the inhomogeneity radius r0 (r(0) > 4 Gpc). Using the Union2 data, we show that the maximum allowed shift r(obs-max) of the observer from the center of the inhomogeneity is about 0.7 r(0), which respects the Copernican principle. The model naturally predicts the existence of a preferred axis and alignment of the low CMB multipoles. However, the constraints on r(obs-max) coming from the magnitude of the CMB dipole remain a severe challenge to the Copernican principle and lead to r(obs-max) < 110 Mpc, even for an inhomogeneity radius as large as r(0) = 7 Gpc.
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microwave background dipole, quasar polarization vectors, probe wmap observations, cosmological constant, matter, anisotropy, galaxies, flow, satellites, inflation
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<Go to ISI>://000292693100002
http://prd.aps.org/abstract/PRD/v84/i2/e023514
http://prd.aps.org/abstract/PRD/v84/i2/e023514
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en
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Πανεπιστήμιο Ιωαννίνων. Σχολή Επιστημών και Τεχνολογιών. Τμήμα Βιολογικών Εφαρμογών και Τεχνολογιών