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ABSTRACT: We present the first systematic follow-up of Planck Sunyaev–Zeldovich effect (SZE) selected candidates down to signal-to-noise (S/N) of 3 over the 5000 deg2 covered by the Dark Energy Survey. Using the MCMF cluster confirmation algorithm, we identify optical counterparts, determine photometric redshifts, and richnesses and assign a parameter, fcont, that reflects the probability that each SZE-optical pairing represents a random superposition of physically unassociated systems rather than a real cluster. The new PSZ-MCMF cluster catalogue consists of 853 MCMF confirmed clusters and has a purity of 90 per cent. We present the properties of subsamples of the PSZ-MCMF catalogue that have purities ranging from 90 per cent to 97.5 per cent, depending on the adopted fcont threshold. Halo mass estimates M500, redshifts, richnesses, and optical centres are presented for all PSZ-MCMF clusters. The PSZ-MCMF catalogue adds 589 previously unknown Planck identified clusters over the DES footprint and provides redshifts for an additional 50 previously published Planck-selected clusters with S/N>4.5. Using the subsample with spectroscopic redshifts, we demonstrate excellent cluster photo-z performance with an RMS scatter in Δz/(1 + z) of 0.47 per cent. Our MCMF based analysis allows us to infer the contamination fraction of the initial S/N>3 Planck-selected candidate list, which is ∼50 per cent. We present a method of estimating the completeness of the PSZ-MCMF cluster sample. In comparison to the previously published Planck cluster catalogues, this new S/N>3 MCMF confirmed cluster catalogue populates the lower mass regime at all redshifts and includes clusters up to z∼1.3.

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]

We use a Bayesian software package to analyse CARMA-8 data towards 19 unconfirmed Planck Sunyaev-Zel'dovich-cluster candidates from Rodrìguez-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 Y500 and an absence of obvious biases. Applying a Planck prior in Y500 to the CARMA-8 gNFW results reduces uncertainties in Y500 and Θ500 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]

We present a sample of 29 galaxy clusters from the XMM-LSS survey over an area of some 5 deg2 out to a redshift of . The sample clusters, which represent about half of the X-ray clusters identified in the region, follow well-defined X-ray selection criteria and are all spectroscopically confirmed. For all clusters, we provide X-ray luminosities and temperatures as well as masses, obtained from dedicated spatial and spectral fitting. The cluster distribution peaks around and keV, half of the objects being groups with a temperature below 2 keV. Our LX– T( z) relation points towards self-similar evolution, but does not exclude other physically plausible models. Assuming that cluster scaling laws follow self-similar evolution, our number density estimates up to are compatible with the predictions of the concordance cosmology and with the findings of previous ROSAT surveys. Our well-monitored selection function allowed us to demonstrate that the inclusion of selection effects is essential for the correct determination of the evolution of the LX– T relation, which may explain the contradictory results from previous studies. Extensive simulations show that extending the survey area to 10 deg2 has the potential to exclude the non-evolution hypothesis, but those constraints on more refined intracluster medium models will probably be limited by the large intrinsic dispersion of the LX– T relation, whatever be the sample size. We further demonstrate that increasing the dispersion in the scaling laws increases the number of detectable clusters, hence generating further degeneracy [in addition to σ8, Ωm, LX– T( z)] in the cosmological interpretation of the cluster number counts. We provide useful empirical formulae for the cluster mass–flux and mass–count rate relations as well as a comparison between the XMM-LSS mass sensitivity and that of forthcoming Sunyaev–Zel'dovich surveys. [ABSTRACT FROM AUTHOR]