Résumé / Abstract Seminaire_IAP
« CDM substructure detection in gravitational lens galaxies  »

Simona Vegetti
Massachusett Inst. Technology (MIT) (Cambridge, Massachusetts, Etats-Unis d'Amérique)

The cold dark matter (CDM) paradigm predicts that a significant number of substructures, with a steeply rising mass function towards lower masses, populates the dark halo of galaxies. In the Milky Way, however, of order 104 substructures are predicted inside the virial radius, whereas only about 20 have been so far observed. This poses a major challenge to the CDM paradigm. New methods are, therefore, required to asses the level of mass substructure in galaxies in the Local Universe and beyond. One such method will be discussed in this talk, which consists of three parts. First, I will present a newly developed adaptive-grid fully Bayesian method, based on an analysis of the surface brightness distribution of highly magnified Einstein rings and arcs, that can detect and precisely quantify substructure in single lens galaxies, even in case of very high mass-to-light ratios. Second, I will discuss how to combine, in a Bayesian statistical sense, the detections of mass substructures from multiple lens galaxies to constrain the substructure mass fraction and the slope of the mass function. Third, I will present new results on the presence of mass substructure in a small sample of the SLACS survey and of the SHARP project.
vendredi 20 septembre 2013 - 11:00
Amphithéâtre Henri Mineur, Institut d'Astrophysique de Paris
Page web du séminaire / Seminar's webpage