Title: The Bolshoi Simulations and Semi-Analytic Models Compared with Observations.
Speaker: Professor Joel Primack
Institute: University of California, Santa Cruz
Time: 14:00, Tuesday, September 4
Place: a meeting room on the 3rd floor of SHAO

Abstract
The Bolshoi and BigBolshoi cosmological dark matter simulations were run with 8.6 billion particles using the WMAP5/7 cosmological parameters in volumes of 250 Mpc/h and 1 Gpc/h with resolutions of 1 kpc/h and 7/kpc/h respectively.  This talk will summarize the key results from these simulations, including comparisons with observations using halo abundance matching.  The cluster concentrations predicted by BigBolshoi are in good agreement with observations.  The galaxy correlation functions and the luminosity-velocity and baryonic-mass-velocity functions agree well with observations, and the predicted velocity function of galaxies agrees with observations above about 100 km/s but may predict more galaxies than observed at lower halo circular velocities.  The fractions of Milky Way mass galaxies with zero, one, two, and more predicted companion galaxies as massive as the Large and Small Magellanic Clouds also agree with observations.  New Semi-Analytic Models based on the Bolshoi halo catalogs and merger trees implement different assumptions concerning galaxy formation, and we are working on comparing them with each other and with observations.

By the way, the July 2012 issue of Sky and Telescope magazine features my article with Trudy Bell about the Bolshoi simulation (https://dl.dropbox.com/u/5495083/Sky%26Telescope%20Bolshoi%20Article.pdf), and I have an "expert feature" article on supercomputing in cosmology coming out in the October 2012 issue of IEEE Spectrum.