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We present a study of the central radio activity of galaxy clusters at high redshift. Using a large sample of galaxy clusters at 0.7 < z < 1.5 from the Massive and Distant Clusters of Wide-field Infrared Survey Explorer Survey and the Faint Images of the Radio Sky at Twenty-Centimeters 1.4 GHz catalog, we measure the fraction of clusters containing a radio source within the central 500 kpc, which we term the cluster radio-active fraction, and the fraction of cluster galaxies within the central 500 kpc exhibiting radio emission. We find tentative (2.25σ) evidence that the cluster radio-active fraction increases with cluster richness, while the fraction of cluster galaxies that are radioluminous (W Hz−1) does not correlate with richness at a statistically significant level. Compared to that calculated at 0 < z < 0.6, the cluster radio-active fraction at 0 < z < 1.5 increases by a factor of 10. This fraction is also dependent on the radio luminosity. Clusters at higher redshift are much more likely to host a radio source of luminosity W Hz−1 than are lower-redshift clusters. We compare the fraction of radioluminous cluster galaxies to the fraction measured in a field environment. For 0.7 < z < 1.5, we find that both the cluster and field radioluminous galaxy fraction increases with stellar mass, regardless of environment, though at fixed stellar mass, cluster galaxies are roughly 2 times more likely to be radioluminous than field galaxies. [ABSTRACT FROM AUTHOR]

We present a multiwavelength investigation of the radio galaxy population in the galaxy cluster MOO J1506+5137 at z = 1.09 ± 0.03, which in previous work we identified as having multiple complex radio sources. The combined data set used in this work includes data from the Low-Frequency Array Two-meter Sky Survey, NSF's Karl G. Jansky Very Large Array, the Robert C. Byrd Green Bank Telescope, the Spitzer Space Telescope, and the Dark Energy Camera Legacy Survey. We find that there are five radio sources, which are all located within 500 kpc (∼1′) of the cluster center and have radio luminosities P1.4 GHz > 1.6 × 1024 W Hz−1. The typical host galaxies are among the highest stellar mass galaxies in the cluster. The exceptional radio activity among the massive galaxy population appears to be linked to the dynamical state of the cluster. The galaxy distribution suggests an ongoing merger, with a subgroup found to the northwest of the main cluster. Furthermore, two of the five sources are classified as bent-tail sources, with one being a potential wide-angle tail/hybrid morphology radio source, indicating a dynamic environment. The cluster also lies in a region of the mass–richness plane occupied by other merging clusters in the Massive and Distant Clusters of WISE Survey. The data suggest that during the merger phase, radio activity can be dramatically enhanced, which would contribute to the observed trend of increased radio activity in clusters with increasing redshift. [ABSTRACT FROM AUTHOR]