Large-Scale Structure

 

The study of the large-scale structure of the universe is also undergoing a tremendous growth. In the early 1980's there were less than 5,000 galaxy redshifts known. However, we now have over 50,000 and will soon have more than 1,000,000. Several new surveys such as 2-Degree Field (2dF) Survey and Sloan Digital Sky Survey (SDSS) have recently been completed. Within a few years the 3-dimension al distribution of galaxies in our local universe will be mapped. Furthermore, those structures can be matched to the early time snapshot of density perturbation (temperature fluctuations in CMBR). Since any model of structure formation must explain both the temperature fluctuations in CMBR and the large-scale structures we observe today in the universe, the combination of these two probes is especially powerful.


A large N-body simulation run by Changbom Park and Richard Gott. The simulation uses Park's (1990) particle-mesh, N-body code to evolve 380³ ~ 55 million particles on a 600³ mesh that represents a comoving, periodic cube 600 h-1 Mpc on a side. The background cosmological model is a flat universe with Omega0=0.4, a cosmological constant La large N-body simulation run by Changbom Park and Richard Gott. The simulation uses Park's (1990) particle-mesh, N-body code to evolve 380³ ~ 55 million particles on a 600³ mesh that represents a comoving, periodic cube 600 h-1 Mpc on a side. The background cosmological model is a flat universe with Omega0=0.4, a cosmological constant Lambda0=0.6 , and a Hubble constant h=0.6 . The initial conditions are Gaussian fluctuations with a cold dark matter (CDM) power spectrum corresponding to these values of Omega0 and h . ambda0=0.6 , and a Hubble constant h=0.6 . The initial conditions are Gaussian fluctuations with a cold dark matter (CDM) power spectrum corresponding to these values of Omega0 and h .

By measuring the redshift of a million galaxies, the Sloan Digital Sky Survey is creating a three-dimensional picture of our local neighborhood of the universe.


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