Abstract:  A method we developed recently for the reconstruction of the initial density field in the nearby Universe is applied to the Sloan Digital Sky Survey Data Release 7. A high-resolution N-body constrained simulation (CS) of the reconstructed initial condition, with 3072^3 particles evolved in a 500Mpc box, is carried out and analyzed in terms of the statistical properties of the final density field and its relation with the distribution of SDSS galaxies. We find that the statistical properties of the cosmic web and the halo populations are accurately reproduced in the CS. The galaxy density field is strongly correlated with the CS density field, with a bias that depend on both galaxy luminosity and color. Our further investigations show that the CS provides robust quantities describing the environments within which the observed galaxies and galaxy systems reside. Cosmic variance is greatly reduced in the CS so that the statistical uncertainties can be controlled effectively even for samples of small volumes. Potential applications of the CS are discussed。

Bio:  I am a Professor of Astronomy at University of Science and Technology of China. My research focusses on large scale structure, galaxy formation and active galactic nuclei. I use numerical simulations to understand the formation of dark matter halos, in particular how environmental processes impact halo properties. I develop methods to reconstruct the mass density field and formation history of large scale structures in local Universe, and use the constrained simulations to study the galaxy formation process. I also study the AGN physics and the large scale environment of AGNs.