Combining clustering and abundances of galaxy clusters to test cosmology and primordial non-Gaussianity. (arXiv:1303.0287v1 [astro-ph.CO])

Combining clustering and abundances of galaxy clusters to test cosmology and primordial non-Gaussianity. (arXiv:1303.0287v1 [astro-ph.CO]):
We present the clustering of galaxy clusters as a useful addition to the
common set of cosmological observables. The clustering of clusters probes the
large-scale structure of the Universe, extending galaxy clustering analysis to
the high-peak, high-bias regime. Clustering of galaxy clusters complements the
traditional cluster number counts and observable-mass relation analyses,
significantly improving their constraining power by breaking existing
calibration degeneracies. We use the maxBCG galaxy clusters catalogue to
constrain cosmological parameters and cross-calibrate the mass-observable
relation, using cluster abundances in richness bins and weak-lensing mass
estimates. We then add the redshift-space power spectrum of the sample,
including an effective modelling of the weakly non-linear contribution and
allowing for an arbitrary photometric redshift smoothing. The inclusion of the
power spectrum data allows for an improved self-calibration of the scaling
relation. We find that the inclusion of the power spectrum typically brings a
~50% improvement in the errors on the fluctuation amplitude sigma_8 and the
matter density Omega_m. Finally, we apply this method to constrain models of
the early universe through the amount of primordial non-Gaussianity of the
local type, using both the variation in the halo mass function and in the
cluster bias. We find a constraint on the amount of skewness f_NL = 12 +/- 157
(1 sigma) from the cluster data alone.