Astronomy Tea Talk

In this talk I will show how the powerful combination of sensitive, high-resolution imaging with gravitational lensing can provide direct observational tests of galaxy formation scenarios under the cold dark matter paradigm. In particular, I will discuss how we can place observational constraints on the subhalo mass function by, for the first time, directly measuring masses of substructure in galaxies outside of the Local Group. These measurements can be made even if the satellites are composed purely of dark matter. The imaging used for this project comes from Keck adaptive optics (AO) and Hubble Space Telescope (HST) observations. In many cases the AO imaging is clearly sharper than that obtained with HST, and provides significantly tighter constraints on the mass distribution than the HST data.