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Feb/19/2008 A Demography of Galaxies in Galaxy Clusters with the Spectro-photometric Density Measurement. Joo Heon Yoon 윤주헌 Sukyoung Yi 이석영 Yoon et al. 2008 ApJS in press (astro-ph/0712.1054) Dept. of Astronomy Yonsei Univ.
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Environment Effect Check individual clusters of galaxies. Require homogeneous catalogue. I. Motivation II. Method III. Result J. H. Yoon K. Schawinski S. K. Yi
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Incompleteness of Spectroscopy I. Motivation II. Method III. Result 1.Classical cluster catalogue (e.g. Abell) Based on eye-inspection. Projection effect, time-consuming… 2.Massive database (SDSS, 2dF, …) Systematic Search! Redshift – 3D distribution! (e.g. C4) Fiber collision!! Spectroscopy is incomplete!! In a dense cluster, f spec. ~ 65% Incompleteness Problem!!
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1.SDSS DR5 spectroscopic and photometric survey galaxies. 2.0.05 < z < 0.1 3.Volume limited samples, r<17.77, M r < -20.54 Data I. Motivation II. Method III. Result
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How do we add galaxies missed by spectroscopic survey? Galaxies in a cluster have Color-Magnitude Relation. Cluster Member Selection via CMR I. Motivation II. Method III. Result
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Cluster Finding with spec.+phot. data Measure local density of galaxies where 3σ=1Mpc, and σ v = velocity dispersion For galaxies with spectra. For galaxies without spectra. Select red-sequence galaxies in CMR Finding the Maximum Density Galaxy!! Finding Galaxy Cluster!! I. Motivation II. Method III. Result spectro-photometric density
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Cluster Finding with spec.+phot. data From SDSS I. Motivation II. Method III. Result Yoon, Schawinski, Sheen, Ree, & Yi, 2008 ApJS in Press (astro-ph/0712.1054)
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Efficiency of the New Measurement From SDSS I. Motivation II. Method III. Result CTIO observation supports our method. 92% of completeness by CTIO obs. New density Spec. density CTIO density missing A2670 Our new method. Minimize the incompleteness.
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Galaxy Classification I. Motivation II. Method III. Result From SDSS 1.Consider spectroscopic members 2.Visual Inspection -SDSS optical combined images -Self-consistency -fracdev_r 3.Color Classification 4.Non-cluster Galaxies ρ = 0
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Color & Luminosity vs. Radius I. Motivation II. Method III. Result From SDSS Color & Luminosity NNo clustocentric dependence.
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I. Motivation II. Method III. Result From SDSS Color & Luminosity vs. Radius Color & Morphology CClustocentric dependence < R 200 MMDR is intrisic. The morphology-density relation Stronger in Denser cluster
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Why the Brightest Cluster Galaxy? I. Motivation II. Method III. Result From SDSS von der Linden et al. 2007 : BCG & non-BCG difference Liu et al. 2007 : Different scaling relations. Quillen et al. 2007 : Star formation in BCGs. Secondary of environmental effect? BCGs in simulation Extremely huge Continuously growing BCGs are so special.
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The BCGs vs. Density I. Motivation II. Method III. Result From SDSS Denser Brighter BCGs As well as 2 nd BCGs & 3 rd BCGs No difference in their density dependence.
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I. Motivation II. Method III. Result From SDSS BCGs, 2 nd BCGs, & 3 rd BCGs are redder than Non-cluster galaxies. They are different population. The BCGs vs. NCGs
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I. Motivation II. Method III. Result From SDSS CMR of ETGs Cluster ETGs are optically red. Non-cluster ETGs have a blue tail.
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I. Motivation II. Method III. Result From SDSS Environmental Dependence Gomez et al. 2003
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I. Motivation II. Method III. Result From SDSS Environmental Dependence
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I. Motivation II. Method III. Result From SDSS ρ vs. R clustocentric R/R 200 ρ Red/Blue g - r R/R 200 ρ Galaxy position in clusters Local density effect on galaxy colors >
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Conclusion New density measurement. minimize the incompleteness. A better tool for environment study. New homogenous cluster catalogue. Color radial dependence Morphology-Density relation. Denser Environment Stronger MDR Denser Brighter BCGs Cluster Galaxies Redder than Non-cluster Galaxies. They are different each other. BCGs and other cluster galaxies. show the same M r -density relation. Local galaxy density > Position in cluster New density measurement. mminimize the incompleteness. AA better tool for environment study. New homogenous cluster catalogue. Color radial dependence Morphology-Density relation. Denser Environment Stronger MDR Denser Brighter BCGs Cluster Galaxies Redder than Non-cluster Galaxies. They are different each other. BCGs and other cluster galaxies. show the same M r -density relation. Local galaxy density > Position in cluster
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All color logos
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Measuring Density (Schawinski et al. 2006) DEC RA z DEC RA z Line of Sight 1Mpc I. Motivation II. Method III. Result 3 X σ v
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A Demography of Cluster Galaxies I. Motivation II. Method III. Result From SDSS
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Efficiency of the New Measurement From SDSS I. Motivation II. Method III. Result BCGs are generally in centers. BCG & MDG separation smaller, better.
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Efficiency of the New Measurement From SDSS I. Motivation II. Method III. Result CMR efficiency test with spectroscopic, early-type (fracdev_r > 0.95) member galaxies. Completeness = Purity = 90% cover 15% contamination
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Efficiency of the New Measurement From SDSS I. Motivation II. Method III. Result Our new density parameter Good tracer of cluster size and mass.
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From SDSS Spectrum analysis Line indices, SFR, etc. ― Clustocentric radius SH’s SAM clusters with Khochfar’s semi-analytical model vs. Observed clusters Constrain SAM. Future Study
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