  The S-Z effect and Faraday rotation from halos are examined over a wide mass
range, an including gas condensation and magnetic field evolution.
Contributions to the CMB angular power spectrum are evaluated for galaxy
clusters, galaxy groups and galaxies. Smaller mass halos are found to play a
more important role than massive halos for the B-mode polarisation associated
with the S-Z CMB anisotropies. The B-modes from Faraday rotation dominate the
secondary B-modes caused by gravitational lensing at l > 3000. Measurement of
B-mode polarisation in combination with the S-Z power spectrum can potentially
provide important constraints on intracluster magnetic field and gas evolution
at early epochs.
