University of Waterloo
200 University Avenue West
Waterloo, Ontario, Canada N2L 3G1
Phone: (519) 888-4567 ext 32215
Fax: (519) 746-8115
Department of Astronomy
Dr. van den Bosch's research focusses on various aspects of cosmology, large scale structure, and galaxy formation. Among other topics, he studies the Galaxy-Dark Matter Connection using Halo Occupation Statistics, models the formation and evolution of disk galaxies, constrains cosmological parameters using galaxies as mass tracers, uses galaxy groups to study galaxy quenching, and uses constrained simulations to model the local Universe.
Halo occupation modeling is a popular technique for interpreting galaxy clustering, informing galaxy formation physics, and constraining cosmological parameters. It models the probabilistic relation between galaxies and dark matter halos and is the premier tool for interpreting the clustering and lensing of galaxies. I show that an application to galaxy clustering and galaxy-galaxy lensing data from the Sloan Digital Sky Survey yields constraints on cosmological parameters that are in clear tension with Planck constraints from the temperature anisotropies in the cosmic microwave background. Although this may signal a potential break-down of `vanilla' LCDM, an alternative explanation is that the data suffers from what is known as assembly bias. I discuss the next generation of halo occupation models that can account for this complication, and discuss prospects of including satellite kinematics and redshift space distortions in the analysis. I also present a new method to avoid the thorny issue of sample variance and end with a brief discussion of how problems with N-body simulations jeopardize our ability to constrain the nature of dark matter.
Light refreshments will be provided in PHY 308, prior to the talk.