Studying light propagation in a locally homogeneous universe through an extended Dyer-Roeder approach

Studying light propagation in a locally homogeneous universe through an extended Dyer-Roeder approach

Author Lima, José Ademar Sales de Google Scholar
Busti, Vinicius Consolini Google Scholar
Santos, Rose Clívia Autor UNIFESP Google Scholar
Institution Universidade de São Paulo (USP)
Universidade Federal de São Paulo (UNIFESP)
Abstract Light is affected by local inhomogeneities in its propagation, which may alter distances and so cosmological parameter estimation. in the era of precision cosmology, the presence of inhomogeneities may induce systematic errors if not properly accounted. in this vein, a new interpretation of the conventional Dyer-Roeder (DR) approach by allowing light received from distant sources to travel in regions denser than average is proposed. It is argued that the existence of a distribution of small and moderate cosmic voids (or black regions) implies that its matter content was redistributed to the homogeneous and clustered matter components with the former becoming denser than the cosmic average in the absence of voids. Phenomenologically, this means that the DR smoothness parameter (denoted here by alpha(E)) can be greater than unity, and, therefore, all previous analyses constraining it should be rediscussed with a free upper limit. Accordingly, by performing a statistical analysis involving 557 type Ia supernovae (SNe Ia) from Union2 compilation data in a flat ACDM model, we obtain for the extended parameter alpha(E) = 1.26(-0.54)(+0.68) (1 sigma). the effects of aE are also analyzed for generic ACDM models and flat XCDM cosmologies. for both models, we find that a value of aE greater than unity is able to harmonize SNe Ia and cosmic microwave background observations thereby alleviating the well-known tension between low and high redshift data. Finally, a simple toy model based on the existence of cosmic voids is proposed in order to justify why alpha(E) can be greater than unity as required by supernovae data.
Language English
Sponsor Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)
Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)
Date 2014-03-04
Published in Physical Review D. College Pk: Amer Physical Soc, v. 89, n. 6, 5 p., 2014.
ISSN 1550-7998 (Sherpa/Romeo, impact factor)
Publisher Amer Physical Soc
Extent 5
Access rights Closed access
Type Article
Web of Science ID WOS:000333106800008

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