Multi-frequency imaging of the galaxy cluster Abell 2163 using the
  Sunyaev-Zel'dovich Effect
  We used the APEX-SZ and LABOCA bolometer cameras on the APEX telescope to map
the decrement of the Sunyaev-Zeldovich effect at 150 GHz and the increment at
345 GHz toward the galaxy cluster Abell 2163. The SZE images were used to model
the radial density and temperature distribution of the ICM, and to derive the
gas mass fraction in the cluster under the assumption of hydrostatic
equilibrium. We used the isothermal beta model to fit the SZE
decrement/increment radial profiles. We performed a simple, non-parametric
de-projection of the radial density and temperature profiles, in conjunction
with XMM-Newton X-ray data, under the simplifying assumption of spherical
symmetry. We combined the peak SZE signals derived in this paper with published
SZE measurements of this cluster to derive the cluster line-of-sight bulk
velocity and the central Comptonization, using priors on the ICM temperature.
We find that the best-fit isothermal model to the SZE data is consistent with
the ICM properties implied by the X-ray data, particularly inside the central 1
Mpc radius. Although the assumptions of hydrostatic equilibrium and spherical
symmetry may not be optimal for this complex system, the results obtained under
these assumptions are consistent with X-ray and weak-lensing measurements. This
shows the applicability of the simple joint SZE and X-ray de-projection
technique described in this paper for clusters with a wide range of dynamical
states. (Abridged)
