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Galaxy in Real Life and Simulations (Leiden, 17/09/2008)

Galaxy in Real Life and Simulations (Leiden, 17/09/2008). When and Where Did Early-Type Galaxies Form?.

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Galaxy in Real Life and Simulations (Leiden, 17/09/2008)

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  1. 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.]

  2. 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?”

  3. Origin of Environmental Dependence N-body simulation of a massive cluster (Yahagi et al. 2005) z = 30 z = 5 ★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 z = 3 z = 2 MOIRCS (NIR) 4’×7’ 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. Suprime-Cam (Opt) 34’×27’ z = 1 z = 0 M=6×1014 M◎ 20×20Mpc2 (co-moving)

  4. Panoramic Imaging and Spectroscopy ofCluster Evolution with Subaru 17 X-ray detected clusters at 0.4 < z < 1.45 (~70% completed) ACS(3.5’) 1.14 XMM XMMU2235.3-2557 223520.6 -255742.0 1.393 3.0 VRi’z’ XMMXCSJ2215.9-1738 221558.5 -173802.5 1.45 4.4 VRi’z’ XMM z~1.4 XMM Kodama et al. (2005)

  5. High Redshift Radio Galaxies(HzRG) with Subaru, VLT, and Spitzer 7 confirmed proto-clusters at 2 < z < 5.2 associated to radio galaxies Overdense in Lyman-α emitters by a factor 3—5. Name redshift NIR Spitzer Lya spectra others PKS 1138-262 2.16 JHKs 3.6--8.0 16 NIR/Opt Ha, VLA, Chandra, SCUBA 4C 23.56 2.48 JHKs 3.6--8.0 NIR Ha USS 1558-003 2.53 JHKs 3.6--8.0 USS 0943-242 2.92 JHKs 3.6--24.0 29 Opt MRC 0316-257 3.13 JHKs 3.6--8.0 32 NIR TNJ 1338-1942 4.11 JHKs 3.6--8.0 37 Suprime-Cam, VLA, MAMBO TNJ 0924-2201 5.19 JHKs 3.6--24.0 6 Suprime-Cam/ACS (LBGs) Kodama et al. (2007), De Breuck et al. (Spitzer HzRGs)

  6. ACS/HST RXJ0152-13 at z=0.83 VRizK photometry + 200 spec. objects

  7. Panoramic Views of Cluster Assembly Spatial distribution of phot-z members (Δz =－0.05~+0.03) CL 0016+16 (BVRi’z’) RXJ 0152.7-1357 (VRIz’) z = 1 z=0.83 (7Gyr ago) z=0.55 (5.4Gyr ago) simulation Kodama, et al. (2005)

  8. Spectroscopic Confirmation of LSS CL 0016+16 (z=0.55) RXJ 0152.7-1357 (z=0.83) FOCAS 30 Mpc (co-moving) 0.548 0.547 0.550 0.835 0.546 0.844 0.547 0.837 0.842 0.550 0.844 0.549 0.745 0.782 0.835 0.542 ~200-300 redshifts per cluster Physical association of most of the structures have been confirmed! Tanaka, TK, et al. (2005b; 2007)

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

  10. high med low Sharp Colour Transition in Groups/Filaments 銀河の色は中間的な環境で急激に変化する RXJ1716 Cluster （z=0.81） （赤い銀河の割合） high ～ cluster core med ～ group / filament low ～ field Koyama, TK,et al. (2008), accepted by MNRAS, arXiv:0809.2795

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

  12. Spatial Distribution of the 15μm sources f(15μm) > 67 μJy A void of 15um sources at the center! Koyama, TK, et al. (2008), arXiv:0809.2795 15 μm galaxies are preferentially found in medium density regions.

  13. 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) “specific star formation rate” large z’－L15 　⇔　large SF efficiency High SSFR

  14. Interacting Galaxies in the 15μm sources Subaru (optical) 16” = 130kpc AKARI (NIR) Koyama, , TK, et al. (2008), MNRAS accepted, arXiv:0809.2795

  15. 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

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

  17. Red sequence of proto-clusters at z~2—2.5 USS1558 (z=2.53) PKS1138 (z=2.16) ● DRG(J-K>2.3) RG 25 arcmin^2 25 arcmin^2 Well-visible red sequence consistent with passive evolution formed at z>3. They are very massive (>1011M◎) !

  18. Red sequence of proto-clusters at z~3 USS0943 (z=2.92) MRC0316 (z=3.13) ● r-JHK ● b-JHK RG Clear excess ofred galaxies consistent with passive evolution formed at z>4, but few massive ones (> 1011M◎) ! not assembled yet !?

  19. Where are the progenitors of massive galaxies at z~3? USS0943 (z=2.923) ● r-JHK ● b-JHK dry mergers simple fading more SF or wet mergers Simple fading alone doesn’t work because there are no massive blue counterparts! SFR of 100 Msun/yr x 1 Gyr = 1011Msun

  20. Spectroscopic follow-up in progress… Extremely unlucky with weather so far! (7 out of 9 Subaru nights were clouded out!) Nevertheless… • Subaru/MOIRCS (NIR, ~30 slits over 7’×4’, R=1300, 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) • Subaru/FOCAS (optical, ~30 slits over 6’φ, R=1000, 5 hrs) 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. • VLT/FORS2 (optical, ~30 slits over 7’×7’, R=1000, 5 hrs) 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. We don’t see many strong emissions... Need to search for continuum break and/or absorption lines.

  21. 4C23.56 (z=2.483) K-band spectra with Subaru/MOIRCS (4.7 hours, R=1300, 4’x7’) 4 Hα emitters including the RG.

  22. Summary for Proto-Clusters (HzRG) • 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 (>1011M◎) are formed rapidly between z=3 and 2 (2~3 Gyr after the Big-bang). • 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?

  23. 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)

  24. 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?

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