Stellar mass function of cluster galaxies at z ∼ 1.5: evidence for reduced quenching efficiency at high redshift

We present the stellar mass functions (SMFs) of passive and star-forming galaxies with a limiting mass of 10(10.1) M-circle dot in four spectroscopically confirmed Spitzer Adaptation of the Red-sequence Cluster Survey (SpARCS) galaxy clusters at 1 : 37 < z < 1 : 63. The clusters have 113 spectroscopically confirmed members combined, with 8-45 confirmed members each. We construct Ks-bandselected photometric catalogs for each cluster with an average of 11 photometric bands ranging from u to 8 mu m. We compare our cluster galaxies to a field sample derived from a similar Ks-band-selected catalog in the UltraVISTA / COSMOS field. The SMFs resemble those of the field, but with signs of environmental quenching. We find that 30 +/- 20% of galaxies that would normally be forming stars in the field are quenched in the clusters. The environmental quenching e ffi ciency shows little dependence on projected cluster-centric distance out to similar to 4 Mpc, providing tentative evidence of pre-processing and/or galactic conformity in this redshift range. We also compile the available data on environmental quenching efficiencies from the literature, and find that the quenching e ffi ciency in clusters and in groups appears to decline with increasing redshift in a manner consistent with previous results and expectations based on halo mass growth.