Local versus global environment: the suppression of star formation in the vicinity of galaxy clusters

De Vos, K.; Merrifield, M.R.; Hatch, N.A.

Abstract

In order to examine where, how and why the quenching of star formation begins in the outskirts of galaxy clusters, we investigate the de-projected radial distribution of a large sample of quenched and star-forming galaxies (SFGs) out to 30í µí± 500 around clusters. We identify the SFG sample using radio continuum emission from the Low-Frequency Array Two-metre Sky Survey. We find that the SFG fraction starts to decrease from the field fraction as far out as 10í µí± 500 , well outside the virial radius of the clusters. We investigate how the SFG fraction depends on both large-scale and local environments, using radial distance from a cluster to characterise the former, and distance from 5th nearest neighbour for the latter. The fraction of SFGs in high-density local environments is consistently lower than that found in low-density local environments, indicating that galaxies' immediate surroundings have a significant impact on star formation. However, for high-mass galaxies-and low mass galaxies to a lesser extent-high-density local environments appear to act as a protective barrier for those SFGs that survived this pre-processing, shielding them from the external quenching mechanisms of the cluster outskirts. For those galaxies that are not in a dense local environment, the global environment causes the fraction of SFGs to decrease toward the cluster centre in a manner that is independent of galaxy mass. Thus, the fraction of SFGs depends on quite a complex interplay between the galaxies' mass, their local environment, and their more global cluster-centric distance.

• Journal Article Type: Article
• Acceptance Date: Jun 3, 2024
• Online Publication Date: Jun 5, 2024
• Publication Date: 2024-07
• Deposit Date: Jun 12, 2024
• Publicly Available Date: Jun 12, 2024
• Journal: Monthly Notices of the Royal Astronomical Society
• Print ISSN: 0035-8711
• Electronic ISSN: 1365-2966
• Publisher: Oxford University Press
• Peer Reviewed: Peer Reviewed
• Volume: 531
• Issue: 4
• Pages: 4383–4390
• DOI: https://doi.org/10.1093/mnras/stae1403
• Keywords: surveys, galaxies: clusters: general, galaxies: evolution, galaxies: groups: general, galaxies: star formation