CARMA observations of massive Planck-discovered cluster candidates at z≳ 0.5 associated with WISE overdensities: breaking the size-flux degeneracy.

We use a Bayesian software package to analyse CARMA-8 data towards 19 unconfirmed Planck Sunyaev-Zel'dovich-cluster candidates from Rodríguez-Gonzálvez et al. that are associated with significant overdensities in WISE. We use two cluster parameterizations, one based on a (fixed shape) generalized-NFW (gNFW) pressure profile and another on a β gas density profile (with varying shape parameters) to obtain parameter estimates from the CARMA-8 data for the nine CARMA-8-detected clusters. Results from the β model show that our cluster candidates exhibit a heterogeneous set of brightness-temperature profiles. Comparison of Planck and CARMA-8 measurements show good agreement in Y₅₀₀500 and an absence of obvious biases. Applying a Planck prior in Y₅₀₀ to the CARMA-8 gNFW results reduces uncertainties in Y₅₀₀ and ⊖₅₀₀ dramatically (by a factor >4), relative to the independent Planck or CARMA-8 measurements. From this combined analysis, we find that our sample is comprised of massive (Y₅₀₀ ranging from 3.3_-0.2 ^+0.2 to 10_{-1.5 +1.1} ×10^-4 arcmin², sd=2.2×10^-4), relatively compact (θ₅₀₀ ranging from 2.1_-0.3 ^+0.1 to 5.5_-0.8^+0.2 arcmin, sd=1.0) systems. Spectroscopic Keck/MOSFIRE data confirmed a galaxy member of one of our cluster candidates at z = 0.565. At the preferred photometric redshift of 0.5, we estimate the cluster mass M₅₀₀ ≈ 0.8 ± 0.2 × 1015M_⊙. We here demonstrate a powerful technique to find massive clusters at intermediate (z 0.5) redshifts using a cross-correlation between Planck and WISE data, with high-resolution CARMA-8 follow-up. We also use the combined capabilities of Planck and CARMA-8 to obtain a dramatic reduction, by a factor of several, in parameter uncertainties. [ABSTRACT FROM AUTHOR]