We present the Massive and Distant Clusters of WISE Survey (MaDCoWS), a search for galaxy clusters at 0.7 z 1.5 based upon data from the W ide-field Infrared Survey Explorer (WISE ) mission. MaDCoWS is the first cluster survey capable of discovering massive clusters at these redshifts over the full extragalactic sky. The search is divided into two regions -the region of the extragalactic sky covered by Pan-STARRS (δ > −30 • ) and the remainder of the southern extragalactic sky at δ < −30 • for which shallower optical data from SuperCOSMOS Sky Survey are available. In this paper we describe the search algorithm, characterize the sample, and present the first MaDCoWS data release -catalogs of the 2433 highest amplitude detections in the WISE -Pan-STARRS region and the 250 highest amplitude detections in the WISE -SuperCOSMOS region. A total of 1723 of the detections from the WISE -Pan-STARRS sample have also been observed with the Spitzer S pace Telescope, providing photometric redshifts and richnesses, and an additional 64 detections within the WISE -SuperCOSMOS region also have photometric redshifts and richnesses. Spectroscopic redshifts for 38 MaDCoWS clusters with IRAC photometry demonstrate that the photometric redshifts have an uncertainty of σ z /(1 + z) 0.036. Combining the richness measurements with Sunyaev-Zel'dovich observations of MaDCoWS clusters, we also present a preliminary mass-richness relation that can be used to infer the approximate mass distribution of the full sample. The estimated median mass for the WISE -Pan-STARRS catalog is M 500 = 1.6 +0.7 −0.8 × 10 14 M , with the Sunyaev-Zel'dovich data confirming that we detect clusters with masses up to M 500 ∼ 5 × 10 14 M (M 200 ∼ 10 15 M ).

We present 190 galaxy cluster candidates (most at high redshift) based on galaxy overdensity measurements in the Spitzer /IRAC imaging of the fields surrounding 646 bent, double-lobed radio sources drawn from the Clusters Occupied by Bent Radio AGN (COBRA) Survey. The COBRA sources were chosen as objects in the VLA FIRST survey that lack optical counterparts in the Sloan Digital Sky Survey (SDSS) to a limit of m r = 22, making them likely to lie at high redshift. This is confirmed by our observations: the redshift distribution of COBRA sources with estimated redshifts peaks near z = 1, and extends out to z ≈ 3. Cluster candidates were identified by comparing our target fields to a background field and searching for statistically significant (≥ 2σ) excesses in the galaxy number counts surrounding the radio sources; 190 fields satisfy the ≥ 2σ limit. We find that 530 fields (82.0%) have a net positive excess of galaxies surrounding the radio source. Many of the fields with positive excesses but below the 2σ cutoff are likely to be galaxy groups. Forty-one COBRA sources are quasars with known spectroscopic redshifts, which may be tracers of some of the most distant clusters known.

We present confirmation of the cluster MOO J1142+1527, a massive galaxy cluster discovered as part of the Massive and Distant Clusters of WISE Survey. The cluster is confirmed to lie at z = 1.19, and using the Combined Array for Research in Millimeter-wave Astronomy we robustly detect the Sunyaev-Zel'dovich (SZ) decrement at 13.2σ. The SZ data imply a mass of M 200m = (1.1 ± 0.2) × 10 15 M e , making MOO J1142+1527 the most massive galaxy cluster known at z > 1.15 and the second most massive cluster known at z > 1. For a standard ΛCDM cosmology it is further expected to be one of the ∼5 most massive clusters expected to exist at z 1.19 over the entire sky. Our ongoing Spitzer program targeting ∼1750 additional candidate clusters will identify comparably rich galaxy clusters over the full extragalactic sky.

We present the results from a pilot study with the Karl G. Jansky Very Large Array (JVLA) to determine the radio morphologies of extended radio sources and the properties of their host-galaxies in 10 massive galaxy clusters at z ∼ 1, an epoch in which clusters are assembling rapidly. These clusters are drawn from a parent sample of WISE -selected galaxy clusters that were cross-correlated with the VLA Faint Images of the Radio Sky at Twenty-Centimeters survey (FIRST) to identify extended radio sources within 1 of the cluster centers. Out of the ten targeted sources, six are FR II sources, one is an FR I source, and three sources have undetermined morphologies. Eight radio sources have associated Spitzer data, 75% presenting infrared counterparts. A majority of these counterparts are consistent with being massive galaxies. The angular extent of the FR sources exhibits a strong correlation with the cluster-centric radius, which warrants further investigation with a larger sample.

We present CARMA 30 GHz Sunyaev-Zel'dovich (SZ) observations of five high-redshift (z 1), infrared-selected galaxy clusters discovered as part of the all-sky Massive and Distant Clusters of WISE Survey (MaDCoWS). The SZ decrements measured toward these clusters demonstrate that the MaDCoWS selection is discovering evolved, massive galaxy clusters with hot intracluster gas. Using the SZ scaling relation calibrated with South Pole Telescope clusters at similar masses and redshifts, we find these MaDCoWS clusters have masses in the range M 200 ≈ 2−6×10 14 M ⊙ . Three of these are among the most massive clusters found to date at z 1, demonstrating that MaDCoWS is sensitive to the most massive clusters to at least z = 1.3. The added depth of the AllWISE data release will allow all-sky infrared cluster detection to z ≈ 1.5 and beyond.