The Intracluster Plasma: a Universal Pressure Profile?
  The pressure profiles of the Intracluster Plasma in galaxy clusters show a
wide variance when observed in X rays at low redshifts z<0.2. We find the
profiles to follow two main patterns, featuring either a steep or a shallow
shape throughout both core and outskirts. We trace these shapes back to a
physical dichotomy of clusters into two classes, marked by either low entropy
(LE) or high entropy (HE) throughout. From X-ray observations and
Sunyaev-Zel'dovich stacked data at higher 0.2<z<0.4, we elicit evidence of an
increasing abundance of HEs relative to LEs. We propose this to constitute a
systematic trend toward high z; specifically, we predict the pressure profiles
to converge into a truly universal HE-like template for z>0.5. We submit our
physical templates and converging trend for further observational tests, in
view of the current and upcoming measurements of individual, stacked, and
integrated Sunyaev-Zel'dovich signals.
