CLUSTER-VOID DEGENERACY BREAKING: DARK ENERGY, PLANCK, AND THE LARGEST CLUSTER AND VOID

摘要

Combining galaxy cluster and void abundances breaks the degeneracy between mean matter density Omega(m) and power-spectrum normalization sigma(8). For the first time for voids, we constrain Omega(m) = 0.21 +/- 0.10 and sigma(8) = 0.95 +/- 0.21 for a flat. CDM universe, using extreme-value statistics on the claimed largest cluster and void. The Planck-consistent results detect dark energy with two objects, independently of other dark energy probes. Cluster-void studies are also complementary in scale, density, and nonlinearity, and are of particular interest for testing modified-gravity models.