Subaru First-Light Deep Photometry of Galaxies in A 851 Field
[摘要] Wereportontheresultsofopticalandnear-infraredphotometryoftheclusterofgalaxiesA851(=CL0939+4713)carriedoutasoneofthefirst-lightobservationsofthe8.2mSubarutelescopeonMaunaKea.Imagesassharpas0″.3FWHMinK′and0″.45inRwereobtainedintheseobservations.The3σlimitingmagnitudesforpointssourcesin0″.3seeingwitha0″.6softwareaperturewereshowntogodowntoR=28.1,J=25.1,andK′;=24.0,respectively,forabout1hourintegration.Subaruphotometryofthegalaxiesinthisclusterhasshowninitscolor-magnitudediagramsawell-definedsequenceoftheearly-typegalaxypopulationthatisconsistentwiththetrackpredictedforasingle-burstpassive-evolutionmodelofgalaxiesatz=0.4.WeattemptedamorphologicalclassificationofgalaxiesintheSubaruR-bandimageusingtheCinmethod,andfoundthatdiscriminationbetweenellipticalsandspiralscanbeachievedfairlyconsistentlywiththetypesassignedbyMORPHsontheHSTF702WimagedowntoRlt;23.AweaklensinganalysismadeontheSubaruR-bandimageyieldedareconstructedsurfacemass-densitydistributionthatshowsasignificantmaximumcorrespondingtothepeakofthesmoothedluminositydistributionofclustergalaxies.Wefoundnosignificantexcessoffaintand/orsmallgalaxiesintheputativeclusterareaaroundthez=2quasarandnodifferenceinthecolorsforgalaxiesinthisareafromthoseinthemainclustereither.Twoextremelyredobjects(ERO)withR–Kgt;6arenewlyidentifiedinthefield.Thecolorsofthereddest,disk-shapedgalaxyR1arefoundcompatiblewiththoseofanunreddenedE/S0galaxyatz=1.6.
[发布日期] [发布机构]
[效力级别] [学科分类] 天文学(综合)
[关键词] "galaxies: clusters of";"galaxies: evolution";"galaxies: photometry";"gravitational lensing";telescopes [时效性]
