Jarvis, Matt J. and Ansarinejad, Behzad and Cappellari, Michele and Bunker, Andrew and Stott, John P. and Bureau, Martin and Croom, Scott M. and Prichard, Laura J. and Davies, Roger L. and Tiley, Alfred L. and Vaughan, Sam P. (2020) 'K-CLASH : Strangulation and ram pressure stripping in galaxy cluster members at 0.3 < z < 0.6.', Monthly notices of the Royal Astronomical Society., 496 (3). pp. 3841-3861.
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.
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|Publisher Web site:||https://doi.org/10.1093/mnras/staa1837|
|Publisher 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.|
|Date accepted:||22 June 2020|
|Date deposited:||27 October 2020|
|Date of first online publication:||26 June 2020|
|Date first made open access:||27 October 2020|
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