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Masami Ouchi (Space Telescope Science Institute) for the SXDS Collaboration Cosmic Web Made of 515 Galaxies at z=5.7 Kona 2005 Ouchi et al. 2005 ApJ, 620, L1 Mapping the Early Universe with Galaxies at z=3-6
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I will report our results for high-z galaxy clustering obtained by the Subaru/XMM-Newton Deep Survey (SXDS). I will show the SXDS data, and highlight 3 results 1) Angular correlation functions of LBGs at z=4 2) Large-scale structures made of Lyα Emitters at z=5.7 3) Forming cluster candidates at z=5.69 and 5.67 I will introduce our on-going studies with HST, Spitzer, and Gemini data in the GOODS fields Outline
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Highly Biased High-z Universe Dense galaxy concentrations←Understood with DH distribution (+GF bias). Distribution of high-z galaxies are highly biased against DM (b=3-5 at z=3-5). How does the large-scale structure of high-z galaxies look like? How do galaxies relate to dark halos? → Wider & deeper survey is needed. Proto-cluster: Redshift spike of Ly break galaxies at z=3.1 (Steidel et al. 1998) r 0 and bias of Ly break galaxies with L>L* (Ouchi et al. 2004) Ouchi et al. (2001) N=1192 8 arcmin
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A multi-wavelength survey under the international collaboration –X-ray:XMM (Watson et al.) –UV: GALEX –Optical: Subaru (Sekiguchi et al.) –NIR: UKIRT (UKDISS[K=25]Almaini et al.) –IR: Spitzer/IRAC (Swire: Lonsdale et al.) Sub-mm:SCUBA (SHADES;Dunlop et al.) –Sub-mm:BLAST (Hughs et al.) –Radio:VLA (Rawlings et al.) (GMRT; Rawlings et al.) The optical data set –Subaru Observatory Key Project (Sekiguchi et al. 2004) –BVRiz with Subaru/Suprime-Cam (Furusawa et al. in prep)~5hr/band/pointing –NB530, NB570=25.3, NB816=26.0 –Subaru/FOCAS (Akiyama et al. in Prep.) –VLT/VIMOS (Simpson/ Saito et al. in prep) Mapping the high-z Universe Subaru/XMM Deep Survey (SXDS) BVRi’z’ 28.227.227.627.526.5 Very Deep + wide-field images SXDS(1.3 deg 2 ) [2 h 18 m 00 s,-5 o 00’00”] ~150 Mpc for z=3-6
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Comparison of Surveyed Areas: Very Deep Multi-band Surveys (i’~27) The best data set for clustering of high-z galaxies SXDS(1.3 deg 2 ) GOODS (0.09 deg 2 ) HUDF(0.002deg 2 )HDF(0.001deg 2 ) FDF(0.01deg 2 ) COSMOS (2deg 2 ; 1/4-1/5 integration in BVRz)
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Large High-z Galaxy Samples Lyman Break Galaxy (LBG) –z~4: 16,920 (i’<27.5; BRi 2 colors) –z~5: 2,768 (z’<26.5; Viz 2 colors + no flux in B) –z~5: 1,293 (z’<26.5; Riz 2 colors + no flux in B,V) –z~6: 133 (z’<26.0; iz 1 color + no flux in B,V,R) Lyα Emitter (LAE) –z~3: 332 (NB503<25.2; BRNB 2 colors) –z~4: 175 (NB570<25.0; BRNB 2 colors) –z~6: 515 (NB816<26.0; RiNB 2 colors) Thanks to the deep & wide field imaging data, we have obtained ~20,000 LBGs and ~1,000 LAEs at z=3.5-6.2 (~x20 times in number on 1 deg 2 sky ) Red galaxies at z~1 is discussed in Kodama et al. (2004; MNRAS, 350, 1005)
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Results of Spectroscopic Follow-up Part of results (for z=5.7 Lyα emitters) Ouchi et al. 2005, ApJ, 620, L1 Part of galaxies in these samples are spectroscopically confirmed. e.g. results in 2003 –20/16920 for z=4 LBGs –19/515 for z=5.7 LAEs
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Sky Distribution z~4 BRi-LBGs (z=3.5-4.5) Red=bright Blue=intermediate Black=faint Gray=masked regions N=16,920
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Sky Distribution z~5 Viz-LBGs (z=4.2-5.2) Red=bright Blue=intermediate Black=faint Gray=masked regions N=2,768
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Sky Distribution z~5 Riz-LBGs (z=4.6-5.2) Red=bright Blue=intermediate Black=faint Gray=masked regions N=1,293
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Sky Distribution z~6 i-dropouts (z=5.6-6.2) Red=bright Blue=intermediate Gray=masked regions N= 133
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Sky Distribution z=3.1 LAEs yellow=LAEs Red =density contour Background: Image N= 332
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Sky Distribution z=5.7 LAEs yellow=LAEs Red =density contour Background: Image N= 515
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1. Angular correlation functions of LBGs at z=4
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10”=350kpc (comoving) Close Companions of LBGs Example i’ band
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Close companions Many LBGs have (a) close companion(s). N pairs ~1,385 for 1”<θ<5” i.e, ~10- 40 h 70 -1 kpc (physical) → for more quantitative analysis, we derive the angular correlation function of LBGs at z=4
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Definitive Detection of the Transition from One-Halo to Halo-Halo Clustering 1. Small scale excess at θ<~5” →r_vir of dark halos with ~10 11 -10 12 h -1 Mo at z=4 z~4 b=(ω g /ω m ) 1/2 Dark matter (non-linear model) Small scale clustering Large-scale clustering N=16,920 2. Large-scale bias (@8Mpc) = 3 → ~10 11 -10 12 h -1 Mo M DH ~10 11-12 Mo
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2. Large-scale structures made of Lyα Emitters at z=5.7
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Large-Scale Structures at z=5.7 Ouchi et al. 2005, ApJ, 620, L1 z=5.7± 0.05 ~40Mpc in line of sight - Galaxy concentrations connected with filaments -10-40 Mpc scale voids Large-scale structures of LAEs are qualitatively similar to those of present-day Universe. →Very early formation of filamentary LSSs made of galaxies The large-scale bias b=3.4 ±1.8 (σ 20 =0.4 for r=20Mpc) is comparable to the LBG clustering (b=3-5) N= 515 Voids
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3. Forming cluster candidates at z=5.69 and 5.67
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Ouchi et al. 2005, ApJ, 620, L1 We made spectroscopic follow-up for densest regions of LAEs (A and B). We have identified two dense concentrations of LAEs. Densest concentrations in the suvey comoving volume→ Progenitors of massive cluster with 1-3x10 14 Mo? concentration A concentration B Densest concentrations of Lyα Emitters in 1x10 6 Mpc 3 5σ-level excess
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Dense Concentrations of LAEs at z=5.7: Facts and Implications Facts: –v~150-180 km/s (→8-10x10 12 Mo, if virialized) –δ ~ 80 –SFRD(cluster) =130 SFRD(field) Implications: –If these are ancestors of today’s massive clusters, the beginning stage of formation of cluster/cluster core whose members will become subsequently old ellipticals→ Forming cluster candidates –Intensive galaxy formation takes place at a specific place of the high-z Universe? → Significant contribution to reionization?? Close-up view of the concentration A SXDF/FCC-A: Forming Cluster Candidate at z=5.69 1 Mpc at z=5.69
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Conclusions I introduced the SXDS optical data and highlighted 3 results for clustering of galaxies at z=3-6, 1)Angular correlation functions of LBGs at z=4 Definitive detection of small & large-scale clustering → two pieces of evidence suggests that LBGs residing in a ~10 12 Mo halo. 2) Large-scale structures made of Lyα Emitters at z=5.7 Detection of filamentary structures with 10-40 Mpc scale voids (large-scale bias b=3.4 ±1.8) → Early formation of filamentary structures of galaxies 3) Forming cluster candidates at z=5.69 and 5.67 Identification of LAE concentrations at z=5.69 and 5.67. Overdensity δ~80, SFR density excess ~ 130 → Intensive galaxy formation takes place at the beginning stage of cluster formation?
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Spectroscopic Identification for Spitzer/IRAC-bright LBGs in the GOODS-N for the GOODS team
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ACS z’ IRAC(ch1/ch2) Spectroscopic Identification for Most Massive Galaxies at z=3-6 Our on-going Project
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