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An Infrared View of Clusters of Galaxies: CLEVL

An Infrared View of Clusters of Galaxies: CLEVL. Myung Gyoon Lee ( 李明均 ) Gwang-Ho Lee ( 李光鎬 ) Seoul National University Seoul, Korea. With AKARI/CLEVL team

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An Infrared View of Clusters of Galaxies: CLEVL

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  1. An Infrared View ofClusters of Galaxies: CLEVL Myung Gyoon Lee (李明均) • Gwang-Ho Lee (李光鎬) Seoul National University Seoul, Korea With AKARI/CLEVL team • (H.M. Lee, M. Im, H.S. Hwang, S.J. Kim, N. Hwang, J.C. Lee, S. Lim, H. Shim, J. Ko, H. Seo, H. Matsuhara, T. Kodama, T. Takagi, T. Nakagawa, T. Wada, Y. Koyama, T. Goto, et al.)

  2. Outline • Overview of clusters of galaxies • An AKARI Mission program: The CLusters of galaxies EVoLution (CLEVL) • Future – WISE study

  3. A New Era for Clusters • Optical: clustering of galaxies (~1950s, Zwicky and Abell) • X-ray: Discovery of Hot ICM • Infrared: Unobscured view of the SFA (NIR/MIR/FIR) • Ground-based: 2MASS → GMT, TMT, eELT etc. • Space: ISO, AKARI, SST, Herschel, WISE → JWST, SPICA, etc. WISE A3395 (z=0.051) AKARI A2219 (z=0.226)

  4. CLEVL • CLusters of galaxies EVoLution studies • AKARI Mission Program (PI: Hyung Mol Lee) • Instruments: AKARI / IRC (N3, N4,S7, S11, L15, L24) • Three Groups • Low-z (z<0.4): Myung Gyoon Lee et al. • Mid-z (0.4<z<1.1): T. Kodama et al. • High-z (z>1.1): T. Takagi et al.

  5. CLEVL: Low-z Clusters • 9 nearby clusters at varying phase of merging

  6. Goals: Low-z Clusters • Effect of cluster merging on SF activity & cluster evolution • to tell triggering or suppressing SF? • to find hidden SF, if any? • Evolution of galaxies falling into clusters • to witness quenching of SF? • Origin of S0 problem • spatial distribution of galaxies with MIR emission and early-type morphology → transformer?

  7. Selection of cluster membership • Using spec-z from SDSS, WINGS, NED

  8. Selection of cluster membership Blue circles: member galaxies selected by cz (± 1500 km s-1)

  9. N3 – Mass / S11 – SFR relations • N3 ← NIR emission coming from old stellar pop. • ◎ N3 is useful to estimate stellar mass of galaxies. • S11 ← MIR emission coming from star-forming region. • ◎ S11 is used as a rough measure of SFR. slope = -0.46 intc = 1.19 σ = 0.16 slope = -0.44 intc = -9.24 σ = 0.42

  10. (N3-S11) vs. SSFR • (N3-S11) color is a good indicator of specific SFRfor galaxies with (N3-S11)>-2.0. Slope = 0.71±0.05 intc = -10.71±0.06

  11. (N3-S11) vs. Age Strong MIR-excess Star-forming Intermediate MIR-excess ages 1~10 Gyr small amount of SF Weak MIR-excess Passively evolving age > 10 Gyr A2255 (Shim et al. 2011)

  12. (N3-S11)Color Distribution • Some clusters (A2219, A2255, A3128) have fraction of high-SFR galaxies larger than 15%. merging core-crossing binary >10 1 Age (Gyr)

  13. Radial variation • MIR-red galaxies are preferentially located in the outskirt.

  14. Spatial distribution of galaxies • Abell 2218 (z = 0.176) • Abell 2219 (z = 0.226) • Abell 3128 (z = 0.060) • and others

  15. Spatial distribution of galaxies • The central region of A2218 is dominated by weak (or intermediate) MIR-excess galaxies. □ MIR-excess ●WMIR ◆ IMIR ★ SMIR Ko et al. 2009

  16. Spatial distribution of galaxies • X-ray: A2219 is elongated in the SE-NW direction. • At R<0.5 R 200,cl, we found several MIR-red galaxies. Boschin et al. 2004 ●WMIR ◆ IMIR ★ SMIR

  17. Spatial distribution of galaxies • Rich, highly substructured cluster: two cores separated by 12 arcmin. • The fraction of strong MIR-excess galaxies with (N3-S11)>0.2 is >20%. • A3128 encountered a tidal interaction with A3125 (~ 6Mpc). Werner et al. 2007 1 Mpc ●WMIR ◆ IMIR ★ SMIR A3125 direction

  18. Spatial distribution of galaxies Compact merger (starting) Complex multiple structures Binary cluster with A3391 Core region in SS

  19. SSFR for clusters • S11 absolute magnitude → SFR • SSFR = ∑ SFR (for SFR > 2.0 M⊙ yr-1within 0.5 R 200,cl) / Mcluster △ Bai et al. 2007 ★ This Study Abell 2219 Abell 2218 Abell 2255

  20. Future – WISE study • Wide-field Infrared Survey Explorer • All-sky (preliminary DR covers 57% of whole sky) • Wavelength:3.4 (W1), 4.6 (W2), 12 (W3) and 22μm (W4) March 2012

  21. Abell 2199 Supercluster • The most mass systems in nearby universe: z = 0.03 • A2199 is kinematically connected to A2197E/W and infalling galaxy groups. • An excellent laboratory for studying galaxy evolution, thanks to a high-density environment and complex structures. Lee et al. in prep.

  22. Summary & Conclusion • AKARI (N3-S11) color is a very efficient tool to find MIR excess galaxies in clusters. • The fraction of star forming galaxies varies among clusters. • Star forming galaxies in clusters are located preferentially in the outskirts. • AKARI opened a new era for galaxy clusters, and WISE also will do!

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