Luminous and Dark Matter in Early Type Galaxies

The formation and evolution of early-type galaxies are still controversial issues. From an observational point of view, whereas substantial progress has been made in understanding star formation history in early-type galaxies, little is known about their internal properties, such as the mass density profile, and their evolution with cosmic time.

I will show that, by applying stellar dynamics and strong and weak-lensing analyses to the largest sample of gravitational lenses known to date, it is possible to gain new insights. I will present measurements of the relative distribution of luminous and dark matter in early-type galaxies out to redshift z=1, and from the innermost stellar dominated regions to several hundred kpcs. The results will be briefly discussed in terms of early-type galaxy formation and evolution scenarios.

Tommaso Treu