Statistics of the Sunyaev-Zel'dovich Effect power spectrum
  Using large numbers of simulations of the microwave sky, incorporating the
Cosmic Microwave Background (CMB) and the Sunyaev-Zel'dovich (SZ) effect due to
clusters, we investigate the statistics of the power spectrum at microwave
frequencies between spherical multipoles of 1000 and 10000. From these virtual
sky maps, we find that the spectrum of the SZ effect has a larger standard
deviation by a factor of 3 than would be expected from purely Gaussian
realizations, and has a distribution that is significantly skewed towards
higher values, especially when small map sizes are used. The standard deviation
is also increased by around 10 percent compared to the trispectrum calculation
due to the clustering of galaxy clusters. We also consider the effects of
including residual point sources and uncertainties in the gas physics. This has
implications for the excess power measured in the CMB power spectrum by the
Cosmic Background Imager and BIMA experiments. Our results indicate that the
observed excess could be explained using a lower value of $\sigma_8$ than
previously suggested, however the effect is not enough to match
$\sigma_8=0.825$. The uncertainties in the gas physics could also play a
substantial role. We have made our maps of the SZ effect available online.
