CfA OIR Division Lunch Talks
Wednesday, June 5, 2013, 11:00 am, Pratt Conference Room

The Largest Structure in the Universe

Changbom Park (Korea Institute for Advanced Study)

We show that the size and richness of the observed largest structures of the universe are consistent with those predicted for the CDM cosmological model. Using the Sloan Digital Sky Survey (SDSS) Main Galaxy sample, we find that the Sloan Great Wall is one of the largest large-scale structures (LSS) when the threshold density for LSS identification is relatively high. We also identified the low-density LSSs in the SDSS sample. To make a quantitative comparison with the CDM model we ran a large cosmological N-body simulation (Horizon Run 2), and performed 200 mock SDSS surveys. The statistical properties of the observed LSSs agree with those of the LSSs identified in the mock surveys astonishingly well. Our mock surveys indicate that a structure like the Sloan Great Wall is usually the largest one and should be found often in the SDSS-like surveys. We conclude that the LSSs identified in current observational samples are consistent with the CDM model, which adopts a homogeneous and isotropic universe with Gaussian primordial fluctuations growing according to General Relativity.