The XXL Survey. V. Detection of the Sunyaev-Zel'dovich Effect of the Redshift 1.9 Galaxy Cluster XLSSU J021744.1-034536 with CARMA

We report the detection of the Sunyaev-Zel'dovich (SZ) effect of galaxy cluster XLSSU J021744.1-034536, using 30 GHz Combined Array for Research in Millimeter-wave Astronomy (CARMA) data. This cluster was discovered via its extended X-ray emission in the XMM- Newton Large Scale Structure survey, the precursor to the XXL survey. It has a photometrically determined redshift z=1.91^+0.19_-0.21, making it among the most distant clusters known, and nominally the most distant for which the SZ effect has been measured. The spherically integrated Comptonization is Y ₅₀₀ = (3.0 ± 0.4) × 10^-12, a measurement that is relatively insensitive to assumptions regarding the size and redshift of the cluster, as well as the background cosmology. Using a variety of locally calibrated cluster scaling relations extrapolated to z ~ 2, we estimate a mass M ₅₀₀ ~ (1-2) × 10¹⁴ M _⊙ from the X-ray flux and SZ signal. The measured properties of this cluster are in good agreement with the extrapolation of an X-ray luminosity-SZ effect scaling relation calibrated from clusters discovered by the South Pole Telescope at higher masses and lower redshifts. The full XXL-CARMA sample will provide a more complete, multi-wavelength census of distant clusters in order to robustly extend the calibration of cluster scaling relations to these high redshifts.