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Properties of Galaxies at High- redshift in the UDS : Environmental Dependence

Properties of Galaxies at High- redshift in the UDS : Environmental Dependence. Seong -Kook Lee, M. IM & J.-W. Kim CEOU@SNU / Feb. 15, 2013. Motivation. Correlation among color (SF), environment and mass. at z~0, density => color : Blanton+05 mass => color : van der Wel08

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Properties of Galaxies at High- redshift in the UDS : Environmental Dependence

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  1. Properties of Galaxies at High-redshift in the UDS : Environmental Dependence Seong-Kook Lee, M. IM & J.-W. Kim CEOU@SNU / Feb. 15, 2013

  2. Motivation • Correlation among color (SF), environment and mass • at z~0, • density => color : Blanton+05 • mass => color : van der Wel08 • at high-z (z~1), • density => color : Cooper+07,Patel+09 • mass => color : Cucciati+10,Grutzbauch+11 Nature vs. ? nurture Aim : investigate dependence among galaxies’ stellar mass, environment, and stellar population properties (incl. color, SF, SFH) and its evolution up to z<2 SSG Workshop

  3. Motivation • Correlation among color (SF), environment and mass Aim : investigate dependence among galaxies’ stellar mass, environment, and stellar population properties (incl. color, SF, SFH) and its evolution up to z>1 We need, (1) deep imaging data, esp. at rest-frame optical (aka. NIR), to reach z < 2 (2) panchromatic coverage from optical to MIR, for robust estimation of stellar population properties • UKIDSS (UKIRT Infrared Deep Sky Survey) / Ultra-Deep Survey (UDS) • deep NIR data from the UKIRT (J, H, & K) • wide coverage of multi-wavelength data • : Optical from SUBARU (B, V, R, I’, and z’) • MIR from Spitzer/IRAC • - ~0.8 sq. degrees, centered at • the Subaru SXDS field (J0218-05) SSG Workshop

  4. DATA • Multi-wavelength Data (12 bands) - optical from Subaru/Suprimecam : B (28.4), V (27.8), R (27.7), i’ (27.7) and z’ (26.7, 3-sigma,AB) - NIR from UKIRT/WFCAM : J(24.9), H(24.2), K(24.6, 5-sigma,AB) - MIR from Spitzer/IRAC : (Ch1 – Ch4,~24,5-sigma,AB) - ~ 50,000 Objects (K-selected, z<2.2) • Photometric Redshift - scatter Δz/(1+z)~ 0.032 SSG Workshop

  5. Stellar Population Analysis • SED-fitting - BC03, Chabrier IMF - delayed SFHs (τ = 0.1 ~ 7.0 Gyr, t = 0.1 Gyr ~ tage) - 0<E(B-V)< 1.5 - Z = 0.2, 0.4, 1.0, & 2.5 Z => find best-fit among more than 200,000 templates SSG Workshop

  6. Environmental Dependence Stellar Population Properties of high-z galaxies depending on the Galaxy Environment (measured by number density) Candidates of high-z (proto-)Clusters and Properties of Cluster Galaxies • Stellar Population Properties of high-z galaxies depending on the Galaxy Environment (measured by number density) • Candidates of high-z (proto-)Clusters and Properties of Cluster Galaxies SSG Workshop

  7. 1. Galaxy Properties @ different Environment • Method 1. Count galaxies within distance < 500/h kpc, and at Δz < 0.032*(1+z) => N_gal 2. To estimate background, calculate N_gal for all galaxies within redshift bin => find mean (N_0) and SD (sigma_N) 3. Define over-(under-)density measure as (N_gal – N_0)/(sigma_N) SSG Workshop

  8. 1. Galaxy Properties @ different Environment • Results : Colour - Density SSG Workshop

  9. 1. Galaxy Properties @ different Environment • Results : Colour – Stellar Mass SSG Workshop

  10. 2. (proto-) Cluster Candidates @ High Redshifts • Method 1. Galaxy counts at each grid point in RA-Dec space (Δ = 12”) within r < 500/h kpc, at each redshift bin (Δz = 0.02) 2. Find large structures of connected bins (> 10 bins) with galaxy counts > 4-sigma SSG Workshop

  11. 2. (proto-) Cluster Candidates @ High Redshifts • Method : continued 3. Connect the structure found in successive redshift bins (> 3-bins) and find central position and redshift for each (proto-) cluster candidates 4. Find galaxies belonging to each (proto-)cluster (within r < 700/h kpc, Δz/(1+z) < 0.032) SSG Workshop

  12. 2. (proto-) Cluster Candidates @ High Redshifts • Results - found 38 candidates within 0.5 < z < 2.0 - recovers 14 (proto-)clusters published (van Breukelen+06,Finoguenov+10,Papovich+10) SSG Workshop

  13. 2. (proto-) Cluster Candidates @ High Redshifts • Results: sSFR dist. (cluster vs. field) SSG Workshop

  14. Summary • Using Deep NIR imaging data from the UKIRT & panchromatic photometric data, • We are investigating stellar population properties of high-redshift galaxies depending on the environment • And, searching galaxy (proto-)cluster candidates at high redshifts, and studying their evolutionary properties. Please stay tuned !! SSG Workshop

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