A Sunyaev-Zel'dovich take on cluster radio haloes -- I. Global scaling
  and bi-modality using Planck data
  Giant radio haloes in galaxy clusters are the primary evidence for the
existence of relativistic particles (cosmic rays) and magnetic fields over Mpc
scales. Observational tests for the different theoretical models explaining
their powering mechanism have so far been obtained through X-ray selection of
clusters, e.g. by comparing cluster X-ray luminosities with radio halo power.
Here we present the first global scaling relations between radio halo power and
integrated Sunyaev-Zel'dovich (SZ) effect measurements, using the Planck
all-sky cluster catalog and published radio data. The correlation agrees well
with previous scaling measurements based on X-ray data, and offers a more
direct probe into the mass dependence inside radio haloes. However, we find no
strong indication for a bi-modal cluster population split between radio halo
and radio quiet objects. We discuss the possible causes for this apparent lack
of bi-modality, and compare the observed slope of the radio-SZ correlation with
competing theoretical models of radio halo origin.
