Physics Colloquium

Deciphering the puzzle(s) of dark matter and dark energy either directly-- e.g., through detecting the dark matter particle -- and/or indirectly-- e.g., through their effects on the growth of structure -- is a top priority in cosmology. I discuss research carried out with state-of-the-art, high resolution cosmological simulations that can shed light in this puzzle in many ways: by helping us test assumptions about these components (comparing simulation results obtained under these assumptions with observation), by revealing potential difficulties about proposed/undergoing observations designed to investigate them, by calibrating our observation analysis & interpretation methods using the controlled environments of simulations, by making predictions for observations to come, etc. I will start with presenting the basics of cosmological simulations and then will present several kinds of results, conclusions and predictions. In particular, rather than delving into a single research direction, e.g., weak lensing as a cosmological probe, I intend to focus on updating the audience on several directions, all of them eventually adding to our effort to understand dark matter, dark energy, and cosmology more generally. Thus, and motivating my topic selection by the LSST science portfolio (http://www.lsst.org/Science/science_portfolio.shtml), I will present results on topics ranging from the structure and accretion history of our galaxy and impications for direct and indirect dark matter detection, to points we must be cautious about when extracting the halo mass function from observations, to mass-to-light ratios, mass-richness relations, fossil groups, etc., as cosmological probes. Lastly, I will briefly discuss the exciting field of Lyman-alpha emission in cosmology.