Probing Galaxy-Scale Halos and Large-Scale Structure with Weak Gravitational Lensing

The presence of dark matter in the Universe is well-established and contributes significantly to structures ranging from galaxies to superclusters. However, the details of the connection between luminous galaxies and the dark matter halos in which they reside are not particularly well-characterised. Weak gravitational lensing is the only direct probe that can measure the total mass profile associated with galaxies over a wide range of radii and does not require assumptions about the dynamical state or baryon content about the system in question. I will describe how we can use lensing to investigate the projected correlation of galaxies with mass from small scales (<few hundred kpc) where individual dark matter halos dominate, out to ~10 Mpc where correlated large-scale structure dominates. We can study how these galaxy-mass correlations behave as a function of galaxy luminosity and redshift, and I will present results from the 20 square degree Deep Lens Survey.