2019MNRAS.485..586R

We quantify the star formation (SF) in the inner cores ( R/R₂₀₀ <=0.3) of 24 massive galaxy clusters at 0.2<= z <=0.9 observed by the Herschel Lensing Survey and the Cluster Lensing and Supernova survey with Hubble. These programmes, covering the rest-frame ultraviolet to far-infrared regimes, allow us to accurately characterize stellar mass-limited ( M_*> 10¹⁰M_☉) samples of star-forming cluster members (not)-detected in the mid- and/or far-infrared. We release the catalogues with the photometry, photometric redshifts, and physical properties of these samples. We also quantify the SF displayed by comparable field samples from the Cosmic Assembly Near-infrared Deep Extragalactic Legacy Survey. We find that in intermediate-z cluster cores, the SF activity is suppressed with respect the field in terms of both the fraction ( F) of star-forming galaxies (SFGs) and the rate at which they form stars ( SFR and s SFR = SFR/ M_*). On average, the F of SFGs is a factor ∼2 smaller in cluster cores than in the field. Furthermore, SFGs present average SFR and s SFR typically ∼0.3 dex smaller in the clusters than in the field along the whole redshift range probed. Our results favour long time-scale quenching physical processes as the main driver of SF suppression in the inner cores of clusters since z ∼0.9, with shorter time-scale processes being very likely responsible for a fraction of the missing SFG population.