# Groupe de Physique Statistique

## Equipe 106, Institut Jean Lamour

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### Séminaire de groupe

 Modified Newtonian Dynamics Benoit Famaey Observatoire Astronomique de Strasbourg jeudi 28 mai 2015 , 10h25 Salle de séminaire du groupe de Physique Statistique In this talk, we review the observational evidence for an intimate connection between the baryonic surface density and the total gravitational field in galaxies. This observational fact presents a fine-tuning problem for the particle dark matter interpretation of mass discrepancies in galaxies. On the other hand, this is naturally explained within the Modified Newtonia Dynamics (MOND) paradigm, hypothesizing an effective breakdown of Newtonian dynamics in the extremely low acceleration regime. However, MOND predictions break down on scales larger than galaxies. Theories modifying the lagrangian of the dark matter sector to account for the MOND phenomenology in galaxies while preserving the predictions of $\Lambda$-CDM on the largest scales are perhaps a promising way to reconcile these conflicting observational facts.