Panoramic Views of Cluster-Scale Assemblies Explored by Subaru Wide-Field Imaging

摘要

WehavestartedPISCESproject;apanoramicimagingandspectroscopicsurveyofdistantclustersonSubaru.Itexploitstheuniquewide-fieldimagingcapabilityofSuprime-Cam,whichprovidesa$$34^{prime} imes27^{prime}$$fieldofviewcorrespondingtoaphysicalareaof$$16 imes13,mathrm{Mpc}^2$$at$$zsim1$$.Weplantotarget15clustersat$$0.4lesssimzlesssim1.3$$.Wereportonourfirstresultsconcerningtheinnerstructuresandlarge-scalestructuresoftwodistantclustersat$$z=0.55$$and0.83togetherwiththeearlierresultsona$$z=0.41$$cluster.Thephotometricredshifttechniquehasbeenappliedtomulti-colordatainordertoremovemostoftheforeground/backgroundgalaxiessoastoisolatetheclustermembercandidates.Wehavefoundlarge-scalefilamentarystructuresaroundtheclusters,extendingoutto$$gt5,mathrm{Mpc}$$fromthecores,aswellascomplexinnerstructures.ThegalaxydistributionsintheinnerregionsoftheclusterslooksimilartotheX-rayintensitymaps,suggestingthatmostoftheopticalstructurestracephysicallyboundsystems.Wealsocomparedthestructuresofthethreeclusterswiththoseofmodelclustersinanumericalsimulation($$N$$-body+semi-analyticmodel)byparameterisingtheshapesoftheiso-densitycontoursofgalaxies,andfoundabroadagreement.Ourresultsthatcluster-scaleassemblytakesplacealongfilamentsduringhierarchicalclusteringneedtobeconfirmedspectroscopicallyinthenearfuture.