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Modélisation précise d’amas de galaxies massifs observés par Hubble et MUSE

Abstract : Clusters of galaxies are large and massive structures containing more than 80% of dark matter. In the cluster core, the mass density can reach a critical threshold making the curvature of space-time large enough to bend light path and then allow multiple convergence of images from the same sources to appear on the observer field of view. Thanks to deep photometric coverage of Abell 2744, a lot of multiply-imaged systems were discovered. Nevertheless, finding them remain a challenge and based on the preserved photometric properties by lensing, I developed a robust method to automatically find them. However, measuring the redshifts for each multiple images remains the best way to surely associate them. The deep coverage of the integral field spectrograph MUSE allowed me to identify a large number of sources ( 514 ) among them 83 were multiple images. Thanks to this large spectroscopic coverage, I built one of the most constrained parametric mass model for lensing cluster to date. The sensitivity raised by this model allow me to probe the influence of outskirts substructures ( at 700 kpc distance ), revealing systematic sources of uncertainties related to the mass model parametrisation ( 6% ). Compared to previous studies, I notice a 10% lower mass in the center ( within 100kpc ) showing one of the benefit of large spectroscopic constraints. This benefit, is smaller on the amplification estimation but shows a significant discrepancy between different mass counterparts in the models, up to 2 times the statistical uncertainties
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Submitted on : Tuesday, January 16, 2018 - 8:55:09 AM
Last modification on : Wednesday, November 20, 2019 - 3:03:08 AM
Long-term archiving on: : Monday, May 7, 2018 - 2:11:52 PM


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  • HAL Id : tel-01685051, version 1



Guillaume Mahler. Modélisation précise d’amas de galaxies massifs observés par Hubble et MUSE. Astrophysique [astro-ph]. Université de Lyon, 2017. Français. ⟨NNT : 2017LYSE1198⟩. ⟨tel-01685051⟩



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