Bispectrum of the Sunyaev-Zel'dovich Effect
  We perform a detailed study of the bispectrum of the Sunyaev-Zel'dovich
effect. Using an analytical model for the pressure profiles of the intracluster
medium, we demonstrate the SZ bispectrum to be a sensitive probe of the
amplitude of the matter power spectrum parameter sigma_8. We find that the
bispectrum amplitude scales as B_SZ ~ sigma_8^{11-12}, compared to that of the
power spectrum, which scales as A_tSZ ~ sigma_8^{7-9}. We show that the SZ
bispectrum is principally sourced by massive clusters at redshifts around
z~0.4, which have been well-studied observationally. This is in contrast to the
SZ power spectrum, which receives a significant contribution from less-well
understood low-mass and high-redshift groups and clusters. Therefore, the
amplitude of the bispectrum at l~3000 is less sensitive to astrophysical
uncertainties than the SZ power spectrum. We show that current high resolution
CMB experiments should be able to detect the SZ bispectrum amplitude with high
significance, in part due to the low contamination from extra-galactic
foregrounds. A combination of the SZ bispectrum and the power spectrum can
sharpen the measurements of thermal and kinetic SZ components and help
distinguish cosmological and astrophysical information from high-resolution CMB
maps.
