The Relation Between Cool Cluster Cores and Herschel-Detected Star Formation in Brightest Cluster Galaxies

We present far-infrared (FIR) analysis of 68 brightest cluster galaxies (BCGs) at 0.08 <z <1.0. Deriving total infrared luminosities directly from Spitzer and Herschel photometry spanning the peak of the dust component (24-500 mu m), we calculate the obscured star formation rate (SFR). 22(-5.3)(+6.2) % of the BCGs are detected in the far-infrared, with SFR = 1-150 M-circle dot yr(-1). The infrared luminosity is highly correlated with cluster X-ray gas cooling times for cool-core clusters (gas cooling time <1 Gyr), strongly suggesting that the star formation in these BCGs is influenced by the cluster-scale cooling process. The occurrence of the molecular gas tracing H alpha emission is also correlated with obscured star formation. For all but the most luminous BCGs (L-TIR > 2 x 10(11) L-circle dot), only a small (less than or similar to 0.4 mag) reddening correction is required for SFR(H alpha) to agree with SFRFIR. The relatively low H alpha extinction (dust obscuration), compared to values reported for the general star-forming population, lends further weight to an alternate (external) origin for the cold gas. Finally, we use a stacking analysis of non-cool-core clusters to show that the majority of the fuel for star formation in the FIR-bright BCGs is unlikely to originate from normal stellar mass loss.