Accessing the Acceleration of the Universe with Sunyaev-Zel'dovich and   X-ray Data from Galaxy Clusters
  By using exclusively the Sunyaev-Zel'dovich effect and X-ray surface brightness data from 25 galaxy clusters in the redshift range 0.023< z < 0.784 we access cosmic acceleration employing a kinematic description. Such result is fully independent on the validity of any metric gravity theory, the possible matter-energy contents filling the Universe, as well as on the SNe Ia Hubble diagram. 
R. F. L. Holanda, J. A. S. Lima, J. V. Cunha
astro-ph.CO gr-qc