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تسجيل مستخدم جديدGeneralized dark matter model with the Euclid satellite
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The concordance model in cosmology, $Lambda$CDM, is able to fit the main cosmological observations with a high level of accuracy. However, around 95% of the energy content of the Universe within this framework remains still unknown. In this work we focus on the dark matter component and we investigate the generalized dark matter (GDM) model, which allows for non-pressure-less dark matter and a non-vanishing sound speed and viscosity. We first focus on current observations, showing that GDM could alleviate the tension between cosmic microwave background and weak lensing observations. We then investigate the ability of the photometric Euclid survey (photometric galaxy clustering, weak lensing, and their cross-correlations) to constrain the nature of dark matter. We conclude that Euclid will provide us with very good constraints on GDM, enabling us to better understand the nature of this fluid, but a non-linear recipe adapted to GDM is clearly needed in order to correct for non-linearities and get reliable results down to small scales.
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xpansion history of the universe and the evolution of cosmic structures by measuring shapes and redshifts of galaxies as well as the distribution of clusters of galaxies over a large fraction of the sky. Although the main driver for Euclid is the nature of dark energy, Euclid science covers a vast range of topics, from cosmology to galaxy evolution to planetary research. In this review we focus on cosmology and fundamental physics, with a strong emphasis on science beyond the current standard models. We discuss five broad topics: dark energy and modified gravity, dark matter, initial conditions, basic assumptions and questions of methodology in the data analysis. This review has been planned and carried out within Euclids Theory Working Group and is meant to provide a guide to the scientific themes that will underlie the activity of the group during the preparation of the Euclid mission.
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