2008/06/30 by A. Saintonge, Amélie Saintonge, Kim‐Vy Tran +3 · 1 citation
Physics and Astronomy · #Astronomy and Astrophysical Research #Astrophysics and Star Formation Studies #Galaxies: Formation, Evolution, Phenomena #astro-ph
paper · pdf · doi:10.1086/592730
published as ApJL, 685 (2008), 113 · 5 pages, 3 figures. Minor changes since v1 include additional data reduction details - this is the published version of the letter
openalex publication_date 2008/09/09 · arxiv created 2008/09/30 · arxiv updated 2009/12/01 · openalex created_date 2016/06/24 · openalex updated_date 2026/08/01
We study the mid-infrared properties of 1315 spectroscopically confirmed members in eight massive ( M vir ≳ 5 × 10 14 M ☉ ) galaxy clusters covering the redshift range from 0.02 to 0.83. The selected clusters all have deep Spitzer /MIPS 24 μm observations, Hubble and ground-based photometry, and extensive redshift catalogs. We observe for the first time an increase in the fraction of cluster galaxies with mid-infrared star formation rates higher than 5 M ☉ yr −1 from 3% at z = 0.02 to 13% at z = 0.83 ( R P ⩽ 1 Mpc). This increase is reproduced even when considering only the most massive members ( M * ⩾ 4 × 10 10 M ☉ ). The 24 μm observations reveal stronger evolution in the fraction of blue/star-forming cluster galaxies than in color-selected samples: the number of dusty, strongly star-forming cluster galaxies increases with redshift, and combining these with the optically defined Butcher-Oemler members [Δ ( B − V ) < − 0.2] doubles the total fraction of blue/star-forming galaxies in the inner Mpc of the clusters to ~23% at z = 0.83. These results, the first of our Spitzer /MIPS Infra-Red Cluster Survey (SMIRCS), support earlier studies indicating that the increase in star-forming members is driven by cluster assembly and galaxy infall, as is expected in the framework of hierarchical formation.