Galaxy in Real Life and Simulations (Leiden, 17/09/2008) When and Where Did Early-Type Galaxies Form? Taddy Kodama (NAOJ), PISCES team [M.Tanaka (ESO), Y. Koyama (Univ of Tokyo)], and HzRG team [De Breuck, Doherty, Seymour, Joel, Kurk, Venemans, Stern, Miley, Kajisawa, I.Tanaka, M.Tanaka, et al.]

Outline  Environmental Effects in Cluster Outskirts (Optical/Space-IR, PISCES, 0.4<z<1.4) “dusty starbursts and truncation in groups”  Massive Galaxy Formation in Proto-Clusters (NIR, HzRG, 2<z<5) “emergence of red sequence at z~2” “When and where did early-type galaxies form?”

z = 30z = 5 z = 2z = 3 z = 0z = 1 Origin of Environmental Dependence N-body simulation of a massive cluster Nature? Ellipticals form early in the highest density peaks while Spirals form later in lower density regions. Nurture? Transformation of Spirals to E/S0s as they assemble to denser regions. MOIRCS (NIR) 4’×7’ 34’×27’ Suprime-Cam (Opt) M=6×10 14 M ◎ 20×20Mpc 2 (co-moving) ★ Optical Survey with S-Cam (0.4<z<1.4): Kodama et al., Tanaka et al., Koyama et al., PISCES team ★ NIR survey with MOIRCS (2<z<5): Kodama et al., Kajisawa et al., HzRG team (Yahagi et al. 2005)

ACS(3.5’) XMM 1.14 Panoramic Imaging and Spectroscopy of Cluster Evolution with Subaru Panoramic Imaging and Spectroscopy of Cluster Evolution with Subaru XMMU VRi’z’ XMMXCSJ VRi’z’ z~1.4 XMM 17 X-ray detected clusters at 0.4 < z < 1.45 (~70% completed) Kodama et al. (2005)

Name redshift NIR Spitzer Lya spectra others PKS JHKs NIR/Opt Ha, VLA, Chandra, SCUBA 4C JHKs NIR Ha USS JHKs USS JHKs Opt MRC JHKs NIR TNJ JHKs Suprime-Cam, VLA, MAMBO TNJ JHKs Suprime-Cam/ACS (LBGs) High Redshift Radio Galaxies (HzRG) with Subaru, VLT, and Spitzer High Redshift Radio Galaxies (HzRG) with Subaru, VLT, and Spitzer 7 confirmed proto-clusters at 2 < z < 5.2 associated to radio galaxies Kodama et al. (2007), De Breuck et al. (Spitzer HzRGs) Overdense in Lyman-α emitters by a factor 3—5.

RXJ at z=0.83 VRizK photometry spec. objects ACS/ HST

z=0.83 (7Gyr ago) z=0.55 (5.4Gyr ago) Spatial distribution of phot-z members (Δz = － 0.05~+0.03) Kodama, et al. (2005) z = 1 simulation Panoramic Views of Cluster Assembly RXJ (VRIz’) CL (BVRi’z’)

Tanaka, TK, et al. (2005b; 2007) 30 Mpc (co-moving) RXJ (z=0.83) FOCAS Spectroscopic Confirmation of LSS Physical association of most of the structures have been confirmed! ~ redshifts per cluster CL (z=0.55)

CL0016 cluster (z=0.55) (Tanaka, et al., in prep.) HSC / WFMOS Millenium Simulation (Springel et al. 2005) A Huge Cosmic Web at z=0.5 over 50 Mpc (80’x80’ by 7 S-Cam ptgs.) S-Cam Traced by red-sequence galaxies in V-I colours

銀河の色は中間的な環境で急激に変化する high med low high ～ cluster core med ～ group / filament low ～ field Sharp Colour Transition in Groups/Filaments RXJ1716 Cluster （ z=0.81 ） Koyama, TK, et al. (2008), accepted by MNRAS, arXiv:

AKARI “Deep” and “Wide” MIR Imaging of a NEP Cluster RXJ1716 (z=0.81) N3 （ 3um ） ＝ 105 min S7 （ 7um ） ＝ 115 min L15 （ 15um ） ＝ 120 min Spitzer AKARI PAH (6-7μ m ) at z=0.8 Subaru SFR > 20 Msun/yr (LIRG, ULIRG) Part of the data comes from CLEVL (mid-z) (PI: H.M.Lee) IR satellite, D=69cm, 1.7<λ<180μm

Spatial Distribution of the 15μm sources Koyama, TK, et al. (2008), arXiv: A void of 15um sources at the center! 15 μm galaxies are preferentially found in medium density regions. f(15μm) > 67 μJy

Dusty star-bursting galaxies in groups/filaments at z~0.8 (Subaru + AKARI) z’ ～ Stellar Mass L15 ～ Star Formation Rate z’ － L15 ＝－ 2.5 log [ f (z’) / f (15) ] ～ SFR / M(star) large z’ － L15 ⇔ large SF efficiency “specific star formation rate” High SSFR

Interacting Galaxies in the 15μm sources Koyama,, TK, et al. (2008), MNRAS accepted, arXiv: ” = 130kpc Subaru (optical) AKARI (NIR)

Summary for PISCES (0.4<z<1.4)  Assembly of Clusters of Galaxies Large scale structures (>10Mpc) are commonly seen as direct evidence for hierarchical growth of clusters.  Origin of Environmental Dependence Enhancement and subsequent truncation of star forming activity is seen in medium-density (group) environment, probably due to galaxy-galaxy interaction.  Down-Sizing as a Function of Environment Time scale of galaxy formation and evolution is dependent on mass of galaxies and environment. Massive, High-density  Less-massive, Lower-density

Stanford et al. (2006) Lidman et al. (2008) Hawk-I data ! XMMJ2235 (z=1.39)XMMJ2215 (z=1.45) When does the red-sequence eventually break down ？ The most distant X-ray clusters to date z(star formation)>2, z(assembly)>1.5

Well-visible red sequence consistent with passive evolution formed at z>3. They are very massive (>10 11 M ◎ ) ! ● DRG(J-K>2.3) RG 25 arcmin^2 PKS1138 (z=2.16) USS1558 (z=2.53) Red sequence of proto-clusters at z~2—2.5

● r-JHK ● b-JHK Clear excess of red galaxies consistent with passive evolution formed at z>4, but few massive ones (> M ◎ ) !  not assembled yet !? RG USS0943 (z=2.92) Red sequence of proto-clusters at z~3 MRC0316 (z=3.13)

● r-JHK ● b-JHK USS0943 (z=2.923) simple fading more SF or wet mergers dry mergers Where are the progenitors of massive galaxies at z~3? SFR of 100 Msun/yr x 1 Gyr = Msun Simple fading alone doesn’t work because there are no massive blue counterparts!

Spectroscopic follow-up in progress…  Subaru/MOIRCS (NIR, ~30 slits over 7’×4’, R=1300, 5 hrs)  Subaru/FOCAS (optical, ~30 slits over 6’φ, R=1000, 5 hrs)  VLT/FORS2 (optical, ~30 slits over 7’×7’, R=1000, 5 hrs) 3 Hα emitters (members) are detected around 4C23.56 (z=2.483) 2 Hα emitters (members) are detected around PKS1138 (z=2.156) 6 redshifts (Lyα+) are measured for USS0943 (z=2.923), of which 2 are members (LAE, b-JHK), while the others are still within 2.4<z<3.1, consistent with our b-JHK selection. 11 redshifts (Lya+) are measured for USS0943 (z=2.923), of which 2 are members, while 4 out of 9 others are still within 2.4<z<3.1, consistent with our JHK selection. Extremely unlucky with weather so far! (7 out of 9 Subaru nights were clouded out!) Nevertheless… We don’t see many strong emissions... Need to search for continuum break and/or absorption lines.

K-band spectra with Subaru/MOIRCS (4.7 hours, R=1300, 4’x7’) 4C23.56 (z=2.483) 4 Hα emitters including the RG.

Summary for Proto-Clusters (HzRG)  Multi-wavelength approach is crucial to disentangle which of the two processes, star formation or mass assembly, is dominant in formation of massive galaxies.  Environmental dependence? Earlier epoch?  Assembly of Proto-Clusters Clustering of many red galaxies (overdensity by a factor of 2-4) around high-z radio-loud galaxies shows the early stage of cluster-scale assembly.  Site of Massive Galaxies Formation Massive galaxies (>10 11 M ◎ ) are formed rapidly between z=3 and 2 (2~3 Gyr after the Big-bang).

Summary for the Distant Cluster Studies with Subaru  Groups in the outskirts of clusters are the key hierarchy for truncation/transformation of galaxies.  The redshift interval of 2<z<3 is the key era for the formation of massive galaxies in high- density regions.  Formation of S0s (and some Es)  Formation of Es (and some S0s)

Questions for Discussion How can we compare clusters at different redshifts? We are likely probing most biased regions (known overdense regions) at any epoch, therefore we can naively expect an evolutionary link between them? But this does not tell us a general formation picture of clusters seen today which can have various assembly histories. How can we normalize luminosity (stellar-mass) functions? We don’t know mass of the systems: velocity dispersion may not work. “overdensity”  “mass” using SAMs? Do we see any environmental dependence at high-z? We expect to see a reversal of star formation-density relation at high-z due to galaxy formation bias? How much star formation is hidden by dust on the red sequence?