Risa Wechsler - Astronomy and Astrophysics

halo occupation: cosmological dependence
fraction of
“field”galaxies
1.0
0.9
0.8
σ 8
0.7
2.0 2.5 3.0 3.5 4.0
denser regions
σ 8
fixed galaxy clustering (now well measured!) + cosmologically dependent dark matter and halo
clustering --> changing bias model.
lower normalization + same galaxy clustering -- same galaxies in more massive halos
--> higher halo occupation, same galaxies live in denser regions