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 ApJS in press (astro-ph/ ) Dept. of Astronomy Yonsei Univ.

Environment Effect  Check individual clusters of galaxies.  Require homogeneous catalogue. I. Motivation II. Method III. Result J. H. Yoon K. Schawinski S. K. Yi

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!!

1.SDSS DR5 spectroscopic and photometric survey galaxies < z < Volume limited samples, r<17.77, M r < Data I. Motivation II. Method III. Result

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

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

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/ )

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.

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

Color & Luminosity vs. Radius I. Motivation II. Method III. Result From SDSS Color & Luminosity NNo clustocentric dependence.

I. Motivation II. Method III. Result From SDSS Color & Luminosity vs. Radius Color & Morphology CClustocentric dependence < R 200 MMDR is intrisic. The morphology-density relation  Stronger in Denser cluster

Why the Brightest Cluster Galaxy? I. Motivation II. Method III. Result From SDSS von der Linden et al : BCG & non-BCG difference Liu et al : Different scaling relations. Quillen et al : Star formation in BCGs.  Secondary of environmental effect? BCGs in simulation Extremely huge Continuously growing BCGs are so special.

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.

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

I. Motivation II. Method III. Result From SDSS CMR of ETGs Cluster ETGs are optically red. Non-cluster ETGs have a blue tail.

I. Motivation II. Method III. Result From SDSS Environmental Dependence Gomez et al. 2003

I. Motivation II. Method III. Result From SDSS Environmental Dependence

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 >

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. mminimize the incompleteness. A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

All color logos

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

A Demography of Cluster Galaxies I. Motivation II. Method III. Result From SDSS

Efficiency of the New Measurement From SDSS I. Motivation II. Method III. Result BCGs are generally in centers. BCG & MDG separation smaller, better.

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

Efficiency of the New Measurement From SDSS I. Motivation II. Method III. Result Our new density parameter  Good tracer of cluster size and mass.

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