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

¹ Departamento de Ciencias FísicasUniversidad Andres Bello, Fernandez Concha 700, 7591538 Las Condes, Santiago, Regin Metropolitana, Chile
e-mail: jnantais@astro-udec.cl
² Laboratoire AIM-Paris-Saclay, CEA/DSM-CNRS-Université Paris Diderot, Irfu/Service d’Astrophysique, CEA Saclay, Orme des Merisiers, 91191 Gif-sur-Yvette, France
³ Australian Astronomical Observatory, PO Box 2915, North Ryde NSW 1670, Australia
⁴ Departamento de Astronomía, Universidad de Concepción, Casilla 160-C, Concepción, Regin del Biobo, Chile
⁵ Department of Astronomy & Astrophysics, University of Toronto, Toronto, Ontario M5S 3H4, Canada
⁶ Department of Physics and Astronomy, University of California-Riverside, 900 University Avenue, Riverside, CA 92521, USA
⁷ Institute of Astronomy, University of Cambridge, Madingley Road, Cambridge CB3 0HA, UK
⁸ Department of Physics and Astronomy, University of California, Irvine, 4129 Frederick Reines Hall, Irvine, CA 92697, USA

Received: 7 April 2016
Accepted: 17 June 2016

Abstract

We present the stellar mass functions (SMFs) of passive and star-forming galaxies with a limiting mass of 10^10.1M_⊙ 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-band-selected photometric catalogs for each cluster with an average of 11 photometric bands ranging from u to 8 μm. 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 efficiency shows little dependence on projected cluster-centric distance out 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 efficiency 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.