Satellite quenching was not important for z ∼ 1 clusters: most quenching occurred during infall

Abstract

We quantify the relative importance of environmental quenching versus pre-processing in z ∼ 1 clusters by analysing the infalling galaxy population in the outskirts of 15 galaxy clusters at 0.8 < z < 1.4 drawn from the GOGREEN and GCLASS surveys. We find significant differences between the infalling galaxies and a control sample; in particular, an excess of massive quiescent galaxies in the infalling region. These massive infalling galaxies likely reside in larger dark matter haloes than similar-mass control galaxies because they have twice as many satellite galaxies. Furthermore, these satellite galaxies are distributed in an NFW profile with a larger scale radius compared to the satellites of the control galaxies. Based on these findings, we conclude that it may not be appropriate to use ‘field’ galaxies as a substitute for infalling pre-cluster galaxies when calculating the efficiency and mass dependency of environmental quenching in high redshift clusters. By comparing the quiescent fraction of infalling galaxies at 1 < R/R200<3 to the cluster sample (R/R200<1) we find that almost all quiescent galaxies with masses >1011 M⊙ were quenched prior to infall, whilst up to half of lower mass galaxies were environmentally quenched after passing the virial radius. This means most of the massive quiescent galaxies in z ∼ 1 clusters were self-quenched or pre-processed prior to infall.

The XXL survey. XLIX. Linking the members star formation histories to the cluster mass assembly in the z=1.98 galaxy cluster XLSSC 122

“…Our results suggest that the oldest members in XLSSC 122 formed and were quenched in the protocluster stage, in agreement with previous attempts to link star formation history and overdensity evolution (e.g. Poggianti et al 2006;Muldrew et al 2018;Werner et al 2022). Our conclusions are also supported by recent observations of z ∼ 3 protoclusters already harbouring quenched galaxies (e.g.…”

“…Nantais et al 2017;Lemaux et al 2019;Strazzullo et al 2019), but the strength of this enhancement seems to depend on the host halo mass-scale (Cerulo et al 2016;Lemaux et al 2019). Clusters of galaxies provide a gradient of dense environments, from the packed cores to the more scarcely populated outskirts (Balogh et al 2000;Poggianti et al 2008;Raichoor & Andreon 2012;Aguerri et al 2018;Pintos-Castro et al 2019;Werner et al 2022) and are thus an ideal laboratory to understand how galaxy evolution is affected by environment at high redshifts.…”

The GOGREEN survey: constraining the satellite quenching time-scale in massive clusters at z ≳ 1

“…In addition, our model may underestimate the role of pre-processing that occurs prior to accretion, especially at high masses where increasing numbers of quenched ultra-massive galaxies have been identified in field surveys (e.g. Forrest et al 2020a,b;Valentino et al 2020;McConachie et al 2021;Werner et al 2022). As discussed in §6.3, including pre-processing within the infall regions surrounding our simulated clusters would lead to a corresponding lengthening of the satellite quenching timescale in Fig.…”

“…The dotted lines are the field quenched fraction results scaled to include the excess quenching due to additional satellite pre-processing in the infall regions of clusters. As discussed in §6.3, the scaling factor is derived from the measurement of the quenched fraction excess between the field and the infall region at z ∼ 1 (Werner et al 2022).…”

“…In this context, a QFE of zero implies that there is no excess quenching between the two probed environments, while a QFE of one indicates that all starforming galaxies in a given environment would be quenched were they to reside in the second (typically higher-density) environment. Werner et al (2022) presents a relevant and recent study of pre-processing for satellites of GOGREEN clusters at 0.8 < z < 1.4 by computing the QFE between coeval cluster, infall (inf, 1 < Rproj/R200 < 3), and control (con) field samples. They find that QFE inf −con strongly correlates with stellar mass, such that high-mass galaxies (M ∼ 10 11 M ) that are star forming in the field are more likely to be quenched in the infall regions relative to their lower-mass (M ∼ 10 10 M ) counterparts.…”