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(Reference retrieved automatically from Web of Science through information on FAPESP grant and its corresponding number as mentioned in the publication by the authors.)

Hubble parameter reconstruction from a principal component analysis: minimizing the bias

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Ishida, E. E. O. [1, 2] ; de Souza, R. S. [1, 2]
Total Authors: 2
[1] Univ Sao Paulo, IAG, BR-05508900 Sao Paulo - Brazil
[2] Univ Tokyo, Inst Phys & Math Universe, Chiba 2778568 - Japan
Total Affiliations: 2
Document type: Journal article
Source: Astronomy & Astrophysics; v. 527, MAR 2011.
Web of Science Citations: 22

Aims. A model-independent reconstruction of the cosmic expansion rate is essential to a robust analysis of cosmological observations. Our goal is to demonstrate that current data are able to provide reasonable constraints on the behavior of the Hubble parameter with redshift, independently of any cosmological model or underlying gravity theory. Methods. Using type Ia supernova data, we show that it is possible to analytically calculate the Fisher matrix components in a Hubble parameter analysis without assumptions about the energy content of the Universe. We used a principal component analysis to reconstruct the Hubble parameter as a linear combination of the Fisher matrix eigenvectors (principal components). To suppress the bias introduced by the high redshift behavior of the components, we considered the value of the Hubble parameter at high redshift as a free parameter. We first tested our procedure using a mock sample of type Ia supernova observations, we then applied it to the real data compiled by the Sloan Digital Sky Survey (SDSS) group. Results. In the mock sample analysis, we demonstrate that it is possible to drastically suppress the bias introduced by the high redshift behavior of the principal components. Applying our procedure to the real data, we show that it allows us to determine the behavior of the Hubble parameter with reasonable uncertainty, without introducing any ad-hoc parameterizations. Beyond that, our reconstruction agrees with completely independent measurements of the Hubble parameter obtained from red-envelope galaxies. (AU)

FAPESP's process: 09/05176-4 - Analysis of the influence of magnetic fields and cold dark matter in the formation and evolution of galaxies
Grantee:Rafael da Silva de Souza
Support type: Scholarships in Brazil - Post-Doctorate