Cosmology

Abstract:

Context. Distant galaxy clusters provide an effective laboratory in which to study galaxy evolution in dense environments and at early cosmic times. Aims. We aim to identify distant galaxy clusters as extended X-ray sources that are coincident with overdensities of characteristically bright galaxies. Methods. We used optical and near-infrared data from the Hyper Suprime-Cam and VISTA Deep Extragalactic Observations (VIDEO) surveys to identify distant galaxy clusters as overdensities of bright, zphot = 0:8 galaxies associated with extended X-ray sources detected in the ultimate XMM extragalactic survey (XXL). Results. We identify a sample of 35 candidate clusters at 0:80 = z = 1:93 from an approximately 4.5 deg2 sky area. This sample includes 15 newly discovered candidate clusters, ten previously detected but unconfirmed clusters, and ten spectroscopically confirmed clusters. Although these clusters host galaxy populations that display a wide variety of quenching levels, they exhibit well-defined relations between quenching, cluster-centric distance, and galaxy luminosity. The brightest cluster galaxies (BCGs) within our sample display colours that are consistent with a bimodal population composed of an old and red sub-sample together with a bluer, more diverse sub-sample. Conclusions The relation between galaxy masses and quenching seem to already be in place at z ~ 1, although there is no significant variation in the quenching fraction with the cluster-centric radius. The BCG bimodality might be explained by the presence of a younger stellar component in some BCGs, but additional data are needed to confirm this scenario.

Abstract:

© 2020 Oxford University Press. All rights reserved. The paper 'Tomographic measurement of the intergalactic gas pressure through galaxy-tSZ cross-correlations' was published inMNRAS, 491, 5464-5480 (2020). After publication a typographical error in our analysis pipeline code was discovered, which slightly affected some of our results. In particular, our implementation of the generalised NFW profile (GNFW) described in Arnaud et al. (2010) lacked a factor of 1 - bH in the calculation of R500. We have corrected this error, re-run our analysis and present our updated results and comments (where applicable) in this manuscript. (i) Table 3 is updated with new best-fitting values. (ii) Likewise, Figs 8 and 9 are also updated with the new values of the best-fitting 1 - bHand<bPe>. (iii) Finally, our combined constraint on bH following this procedure (equation 48) is 1 - bH= 0.75 ± 0.03. While the main conclusions remain unchanged, it is worth pointing out that the best-fitting mass bias value 1 - bH= 0.75 ± 0.03 is now at a ~3-4s tension with the results measured by Planck Collaboration et al. (2016a) (1 - bH= 0.58 ± 0.04), combining tSZ cluster number counts and the TT CMB power spectrum. Consequently, our results can no longer be viewed as evidence of compatibility between the best-fit cosmology and the clustering properties of galaxies in the datasets used. Further, the best-fitting value of the mass bias is no longer at odds with the one derived from hydrodynamical simulations (Biffi et al. 2016), the estimate from CMB lensing mass calibration (Zubeldia & Challinor 2019), and other direct calibration efforts (e.g. Smith et al. 2016; Eckert et al. 2019), which seem to prefer smaller missing mass fractions (1 - bH~ 0.8). Lastly, our results are in agreement with Chiang et al. (2020), who explore the cosmic thermal history using SZ tomography.