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K-CLASH: Strangulation and ram pressure stripping in galaxy cluster members at 0.3 < z < 0.6

Jarvis, Matt J.; Ansarinejad, Behzad; Cappellari, Michele; Bunker, Andrew; Stott, John P.; Bureau, Martin; Croom, Scott M.; Prichard, Laura J.; Davies, Roger L.; Tiley, Alfred L.; Vaughan, Sam P.

K-CLASH: Strangulation and ram pressure stripping in galaxy cluster members at 0.3 < z < 0.6 Thumbnail


Matt J. Jarvis

Behzad Ansarinejad

Michele Cappellari

Andrew Bunker

John P. Stott

Martin Bureau

Scott M. Croom

Laura J. Prichard

Roger L. Davies

Alfred L. Tiley

Sam P. Vaughan


Galaxy clusters have long been theorized to quench the star formation of their members. This study uses integral-field unit observations from the K-band MultiObject Spectrograph (KMOS) – Cluster Lensing And Supernova survey with Hubble (CLASH) survey (K-CLASH) to search for evidence of quenching in massive galaxy clusters at redshifts 0.3 < z < 0.6. We first construct mass-matched samples of exclusively star-forming cluster and field galaxies, then investigate the spatial extent of their H α emission and study their interstellar medium conditions using emission line ratios. The average ratio of H α half-light radius to optical half-light radius (⁠re,Hα/re,Rc⁠) for all galaxies is 1.14 ± 0.06, showing that star formation is taking place throughout stellar discs at these redshifts. However, on average, cluster galaxies have a smaller re,Hα/re,Rc ratio than field galaxies: 〈re,Hα/re,Rc〉 = 0.96 ± 0.09 compared to 1.22 ± 0.08 (smaller at a 98 per cent credibility level). These values are uncorrected for the wavelength difference between H α emission and Rc-band stellar light but implementing such a correction only reinforces our results. We also show that whilst the cluster and field samples follow indistinguishable mass–metallicity (MZ) relations, the residuals around the MZ relation of cluster members correlate with cluster-centric distance; galaxies residing closer to the cluster centre tend to have enhanced metallicities (significant at the 2.6σ level). Finally, in contrast to previous studies, we find no significant differences in electron number density between the cluster and field galaxies. We use simple chemical evolution models to conclude that the effects of disc strangulation and ram-pressure stripping can quantitatively explain our observations.

Journal Article Type Article
Acceptance Date Jun 22, 2020
Online Publication Date Jun 26, 2020
Publication Date 2020-08
Deposit Date Oct 27, 2020
Publicly Available Date Oct 27, 2020
Journal Monthly Notices of the Royal Astronomical Society
Print ISSN 0035-8711
Electronic ISSN 1365-2966
Publisher Royal Astronomical Society
Peer Reviewed Peer Reviewed
Volume 496
Issue 3
Pages 3841-3861
Public URL


Published Journal Article (3.2 Mb)

Copyright Statement
This article has been accepted for publication in Monthly notices of the Royal Astronomical Society. ©: 2020 The Author(s). Published by Oxford University Press on behalf of the Royal Astronomical Society. All rights reserved.

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