Measurements of Secondary Cosmic Microwave Background Anisotropies with
  the South Pole Telescope
  We report cosmic microwave background (CMB) power spectrum measurements from
the first 100 sq. deg. field observed by the South Pole Telescope (SPT) at 150
and 220 GHz. On angular scales where the primary CMB anisotropy is dominant,
ell ~< 3000, the SPT power spectrum is consistent with the standard LambdaCDM
cosmology. On smaller scales, we see strong evidence for a point source
contribution, consistent with a population of dusty, star-forming galaxies.
After we mask bright point sources, anisotropy power on angular scales of 3000
< ell < 9500 is detected with a signal-to-noise > 50 at both frequencies. We
combine the 150 and 220 GHz data to remove the majority of the point source
power, and use the point source subtracted spectrum to detect
Sunyaev-Zel'dovich (SZ) power at 2.6 sigma. At ell=3000, the SZ power in the
subtracted bandpowers is 4.2 +/- 1.5 uK^2, which is significantly lower than
the power predicted by a fiducial model using WMAP5 cosmological parameters.
This discrepancy may suggest that contemporary galaxy cluster models
overestimate the thermal pressure of intracluster gas. Alternatively, this
result can be interpreted as evidence for lower values of sigma8. When combined
with an estimate of the kinetic SZ contribution, the measured SZ amplitude
shifts sigma8 from the primary CMB anisotropy derived constraint of 0.794 +/-
0.028 down to 0.773 +/- 0.025. The uncertainty in the constraint on sigma8 from
this analysis is dominated by uncertainties in the theoretical modeling
required to predict the amplitude of the SZ power spectrum for a given set of
cosmological parameters.
