A Deficit of Faint Red Galaxies in the Possible Large-Scale Structures around the RDCS J1252.9-2927 Cluster at z=1.24

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dc.creatorTanaka, Masayuki
dc.creatorKodama, Tadayuki
dc.creatorKajisawa, Masaru
dc.creatorBower, Richard
dc.creatorDemarco, Ricardo
dc.creatorFinoguenov, Alexis
dc.creatorLidman, Chris
dc.creatorRosati, Piero
dc.date2007-03-07
dc.date.accessioned2026-07-07T11:00:59Z
dc.date.available2026-07-07T11:00:59Z
dc.description(Abridged) We report a discovery of possible large-scale structures around the RDCS J1252.9-2927 cluster at z=1.24 based on photometric redshifts. We carried out multi-band wide-field imaging with Suprime-Cam on the Subaru Telescope and WFCAM on the United Kingdom Infra-Red Telescope (UKIRT). The distribution of photo-z selected galaxies reveals clumpy structures surrounding the central cluster. We compare the observed structure with an X-ray map and find that two of the four plausible clumps show significant X-ray emissions and one with a marginal detection, which strongly suggest that they are dynamically bound systems. Following the discovery of the possible large-scale structure, we carried out deeper SOFI K_s-band imaging with New Technology Telescope on the four plausible clumps. We construct the optical-to-near-infrared colour-magnitude diagrams of the galaxies in the clumps, and find that the colour-magnitude relation (CMR) of the red galaxies in the clumps is sharply truncated below K_s=22. Interestingly, the main cluster shows a clear relation down to K_s=23 (Lidman et al. 2004). We suggest that galaxies follow the 'environment-dependent down-sizing' evolution. Massive galaxies in high density environments first stop forming stars and become red. Less massive galaxies in less dense environments become red at later times. Based on a few assumptions, we predict that the brightest tip of the CMR appears at z~2.5.
dc.description10 pages, 8 figures, accepted for publication in MNRAS
dc.identifierhttps://arxiv.org/abs/astro-ph/0703135
dc.identifierhttp://arxiv.org/abs/astro-ph/0703135
dc.identifierMon.Not.Roy.Astron.Soc.377:1206-1214,2007
dc.identifierdoi:10.1111/j.1365-2966.2007.11671.x
dc.identifier.urihttp://salesiana.dossiersoluciones.com/handle/123456789/187829
dc.subjectAstrophysics
dc.titleA Deficit of Faint Red Galaxies in the Possible Large-Scale Structures around the RDCS J1252.9-2927 Cluster at z=1.24
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