Shown below are maps of SZ effect, which were produced by the MMH hydro code ( Seljak, Burwell and Pen 1999 ). You can also view a movie of gas density evolution with comoving time (in units of mean comoving density), as well as that of gas pressure in units of Compton y. The movies are for a cluster abundance normalized cosmological constant model in a 70Mpc box. Note the logarithmic scale in both cases. One can watch the evolution of gas from cold and uniform to hot and clumpy. The clumps are continuously merging into larger and larger structures, observed as groups and clusters today.

SZ map of cosmological constant model, 2x2 degree

SZ map of tauCDM model, 4x4 degree

SZ map of open CDM model, 4x4 degree