Astronomy Tea Talk

I present our recent measurements of the spatial distribution and the cumulative luminosity function of satellites up to a thousand times fainter than their hosts, as a function of host stellar mass and morphology between redshifts 0.1 and 0.8, using imaging from the COSMOS fields and a rigorous statistical analysis.  I will demonstrate how these measurements provide powerful new constraints for abundance matching and cosmological simulations in the context of both warm and cold dark matter, and how future measurements of faint satellite colors using CANDELS, will provide important distinguishing power between warm and cold dark matter models.  In addition, I will present results from a complementary gravitational lens modeling project in which we use spatially resolved spectra obtained with OSIRIS at Keck to place new constraints on the subhalo mass function.