Abstract
We report direct evidence of pre-processing of the galaxies residing in galaxy groups falling into galaxy clusters drawn from the Local Cluster Substructure Survey (LoCuSS). 34 groups have been identified via their X-ray emission in the infall regions of 23 massive (〈M200〉 = 1015 M⊙) clusters at 0.15 < z < 0.3. Highly complete spectroscopic coverage combined with 24 μm imaging from Spitzer allows us to make a consistent and robust selection of cluster and group members including star-forming galaxies down to a stellar mass limit of M⋆ = 2 × 1010 M⊙. The fraction fSF of star-forming galaxies in infalling groups is lower and with a flatter trend with respect to clustercentric radius when compared to the rest of the cluster galaxy population. At R ≈ 1.3 r200, the fraction of star-forming galaxies in infalling groups is half that in the cluster galaxy population. This is direct evidence that star-formation quenching is effective in galaxies already prior to them settling in the cluster potential, and that groups are favourable locations for this process.
Original language | English |
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Pages (from-to) | L79–L83 |
Number of pages | 5 |
Journal | Monthly Notices of the Royal Astronomical Society |
Volume | 473 |
Issue number | 1 |
Early online date | 12 Oct 2017 |
DOIs | |
Publication status | Published - 1 Jan 2018 |
Keywords
- galaxies: clusters: general
- galaxies: evolution
- galaxies: groups: general
- galaxies: star formation