1. An excess of small-scale gravitational lenses observed in galaxy clusters.
- Author
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Meneghetti M, Davoli G, Bergamini P, Rosati P, Natarajan P, Giocoli C, Caminha GB, Metcalf RB, Rasia E, Borgani S, Calura F, Grillo C, Mercurio A, and Vanzella E
- Abstract
Cold dark matter (CDM) constitutes most of the matter in the Universe. The interplay between dark and luminous matter in dense cosmic environments, such as galaxy clusters, is studied theoretically using cosmological simulations. Observations of gravitational lensing are used to characterize the properties of substructures-the small-scale distribution of dark matter-in clusters. We derive a metric, the probability of strong lensing events produced by dark-matter substructure, and compute it for 11 galaxy clusters. The observed cluster substructures are more efficient lenses than predicted by CDM simulations, by more than an order of magnitude. We suggest that systematic issues with simulations or incorrect assumptions about the properties of dark matter could explain our results., (Copyright © 2020 The Authors, some rights reserved; exclusive licensee American Association for the Advancement of Science. No claim to original U.S. Government Works.)
- Published
- 2020
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