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Context. Oscillation experiments yield strong evidence that at least some neutrinos are massive. As a hot dark-matter component, massive neutrinos would modify the expansion history of the Universe as well as the evolution of cosmological perturbations, differently from cold dark matter or dark energy. Aims. We use the latest release of CFHTLS cosmic-shear(More)
To resolve some unphysical interpretations related to velocity measurements by static observers, we discuss the use of generalized observer sets, give a prescription for defining the speed of test particles relative to these observers, and show that, for any locally inertial frame, the speed of a freely falling material particle is always less than the(More)
Context. Dark energy can be investigated in two complementary ways, by considering either general parameterizations or physically well-defined models. This article follows the second route and explores the observational constraints on quintessence models where the acceleration of our universe is driven by a slow-rolling scalar field. The analysis focuses on(More)
We explore the dynamics and evolution of the Universe at early and late times, focusing on both dark energy and extended gravity models and their astrophysical and cosmological consequences. Modified theories of gravity not only provide an alternative explanation for the recent expansion history of the universe, but they also offer a paradigm fundamentally(More)
The current methods available to estimate gravitational shear from astronomical images of galaxies introduce systematic errors which can affect the accuracy of weak lensing cosmolog-ical constraints. We study the impact of KSB shape measurement bias on the cosmological interpretation of tomographic two-point weak lensing shear statistics. We use a set of(More)
The question of the physical reality of the black hole interior is a recurrent one. An objection to its existence is the well known fact that the velocity of a material particle, refered to the stationary frame, tends to the velocity of light as it approaches the horizon. It is shown, using Kruskal coordinates, that a timelike radial geodesic does not(More)
A light scalar field, minimally or not-minimally coupled to the metric field, is a well-defined candidate for the dark energy, overcoming the coincidence problem intrinsic to the cosmological constant and avoiding the difficulties of parameterizations. We present a general description of the weak gravitational lensing valid for every metric theory of(More)
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