ELUCID—EXPLORING THE LOCAL UNIVERSE WITH RECONSTRUCTED INITIAL DENSITY FIELD. III. CONSTRAINED SIMULATION IN THE SDSS VOLUME

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 conditions, with 3072 3 particles evolved in a box, is carried out and analyzed in terms of the statistical properties of the final density field and its relation with the distribution of Sloan Digital Sky Survey 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 depends 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.