2018/07/02 by Remco F. J. van der Burg, Sean McGee, Herve Aussel +6 · 57 citations
Physics and Astronomy · #Astronomy and Astrophysical Research #Cluster (spacecraft) #Galaxies: Formation, Evolution, Phenomena #Galaxy #Galaxy cluster #Photometry (optics) #Population #Redshift #Satellite galaxy #Star formation #Stellar mass #Stellar, planetary, and galactic studies #astro-ph.GA
paper · pdf · doi:10.1051/0004-6361/201833572
published in Astronomy and Astrophysics 618, A140 (EDP Sciences) · 16 pages, 12 figures, accepted for publication in A&A
arxiv created 2018/07/02 · openalex publication_date 2018/07/09 · openalex created_date 2018/07/10 · arxiv updated 2018/11/07 · openalex updated_date 2026/08/05
We study the abundance of star-forming and quiescent galaxies in a sample of 21 clusters at 0.5 < z < 0.7, detected with the Planck satellite. Thanks to the large volume probed by Planck , these systems are extremely massive, and provide an excellent laboratory to study any environmental effects on their galaxies’ properties. We measure the cluster galaxy stellar mass function (SMF), which is a fundamental observable to study and constrain the formation and evolution of galaxies. Our measurements are based on homogeneous and deep multi-band photometry spanning from the u - to the K s -band for each cluster and are supported by spectroscopic data from different programs. The galaxy population is separated into quiescent and star-forming galaxies based on their rest-frame U−V and V−J colours. The SMF is compared to that of field galaxies at the same redshifts using data from the COSMOS/UltraVISTA survey. We find that the shape of the SMF of star-forming galaxies does not depend on environment, while the SMF of quiescent galaxies has a significantly steeper low-mass slope in the clusters compared to the field. This indicates that a different quenching mechanism is at play in clusters compared to the field, accentuated by a quenched fraction that is much higher in the clusters. We estimate the environmental quenching efficiency ( f EQ ), that is, the probability for a galaxy that would normally be star forming in the field to be quenched due to its environment. The f EQ shows no stellar-mass dependence in any environment, but it increases from 40% in the cluster outskirts to ∼90% in the cluster centres. The radial signature of f EQ provides constraints on where the dominant quenching mechanism operates in these clusters and on what timescale. Exploring these using a simple model based on galaxy orbits obtained from an N-body simulation, we find a clear degeneracy between both parameters. For example, the quenching process may either be triggered on a long (∼3 Gyr) timescale at large radii ( r ∼ 8 R 500 ), or happen well within 1 Gyr at r < R 500 . The radius where quenching is triggered is at least r quench > 0.67 R 500 (95%CL). The ICM density at this location (as probed with XMM-Newton ) suggests that ram-pressure stripping of the cold gas is a likely cause of quenching. In addition to this cluster-quenching mechanism, we find that 20–32%, depending on the cluster-specific quenching process, of accreted galaxies were already pre-processed (i.e. quenched by the surrounding overdensities) before they fell into the clusters.