Tracing mass and light in the universe: Where is the dark matter?

Abstract

How is mass distributed in the Universe? How does it compare with the distribution of light and stars?We address these questions by examining the distribution of mass, determined from weak lensing observations, and starlight, around >105 Sloan Digital Sky Survey MaxBCG groups and clusters as a function of environment and scale, from deep inside clusters to large cosmic scales of 22 h-1 Mpc. The observed cumulative mass-to-light profile, M/L (