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

Motivation Correlation among color (SF), environment and mass Feb SSG Workshop - 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

Motivation Feb SSG Workshop Aim : investigate dependence among galaxies’ stellar mass, environment, and stellar population properties (incl. color, SF, SFH) and its evolution up to z>1 Correlation among color (SF), environment and mass 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 (J )

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)~ Feb SSG Workshop

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

Environmental Dependence 1.Stellar Population Properties of high-z galaxies depending on the Galaxy Environment (measured by number density) 2.Candidates of high-z (proto-)Clusters and Properties of Cluster Galaxies Feb SSG Workshop 1.Stellar Population Properties of high-z galaxies depending on the Galaxy Environment (measured by number density) 2.Candidates of high-z (proto-)Clusters and Properties of Cluster Galaxies

1. Galaxy different Environment Method 1. Count galaxies within distance < 500/h kpc, and at Δz 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) Feb SSG Workshop

1. Galaxy different Environment Results : Colour - Density Feb SSG Workshop

1. Galaxy different Environment Results : Colour – Stellar Mass Feb SSG Workshop

2. (proto-) Cluster 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 Feb SSG Workshop

2. (proto-) Cluster 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) Feb SSG Workshop

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

2. (proto-) Cluster High Redshifts Results: sSFR dist. (cluster vs. field) Feb SSG Workshop

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. Feb SSG Workshop Please stay tuned !!