2018ApJ...853..195W

We present new Herschel observations of four massive, Sunyaev-Zel'dovich effect-selected clusters at 0.3 z 1.1, two of which have also been observed with the Atacama Large Millimeter/submillimeter Array (ALMA). We detect 19 Herschel/Photoconductor Array Camera and Spectrometer (PACS) counterparts to spectroscopically confirmed cluster members, five of which have redshifts determined via CO (4-3) and [C I] (³P₁–³P₀) lines. The mean [C I]/CO line ratio is 0.19 ± 0.07 in brightness temperature units, consistent with previous results for field samples. We do not detect significant stacked ALMA dust continuum or spectral-line emission, implying upper limits on mean interstellar medium (H₂ + H I) and molecular gas masses. An apparent anticorrelation of L_IR with clustercentric radius is driven by the tight relation between star formation rate and stellar mass. We find an average specific star formation rate of log(sSFR/yr^–1) = -10.36, which is below the SFR–M_* correlation measured for field galaxies at similar redshifts. The fraction of infrared-bright galaxies (IRBGs; log(L_IR/L_☉) 10.6) per cluster and average sSFR rise significantly with redshift. For CO detections, we find f_gas∼0.2, comparable to those of field galaxies, and gas depletion timescales of about 2 Gyr. We use radio observations to distinguish active galactic nuclei (AGNs) from star-forming galaxies. At least four of our 19 Herschel cluster members have q_IR 1.8, implying an AGN fraction f_AGN 0.2 for our PACS-selected sample.