Previous
abstract 
Next abstract
We present estimates of the confusion limit to observations of the thermal and kinetic Sunyaev-ZelUdovich (S-Z) effects on arcminute angular scales at millimeter wavelengths. Measurements of the amplitude of the thermal S-Z effect (Comptonization) can be combined with measurements of the X- ray brightness of the cluster to yield values for the Hubble constant, Ho. The ratio of the kinetic and the thermal S-Z effects can be combined with the X-ray gas temperature to yield the radial component of the peculiar velocity of the cluster. The confusion noise to measurement of the thermal S-Z effect has minima at frequencies near 100 and 300 GHz. The estimated 1$\sigma$ noise level for measurements of the Compton y parameter are $\Delta$y J$= 10^{-6}$ and $ 6 x 10^{-6}$ respectively. For a Compton parameter typical of a rich cluster, y = $ 10^{-4}$ , the contribution of confusion to the uncertainty in an estimate of Ho will be 2$\Delta$y/y = 2\% and 12\% respectively. The confusion noise to measurement of the kinetic S-Z effect has a broad minimum near 100 GHz. The estimated 1$\sigma$ noise level for measurements of the radial component of the peculiar velocity is $\Delta v_{r} = 50 (\tau /0.01)^{-1} $ kms$^{-1}$, where $ \tau $ is the optical depth for scattering of the CMB photons. The estimated confusion limit assumes an ideal experiment that suffers no beam dilution, and measures the cluster brightness relative to a reference beam that is sufficiently far from the cluster that it contains negligible S-Z signal. The confusion limits for an actual experiment will be increased by these two factors.
