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 A

pJ, 620, L1

Mapping the Early Universe with Galaxies at z=3-6

• 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=42) Large-scale structures made of Lyα Emitters at z=5.73) 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

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)

r0 and bias of Ly break galaxies with L>L* (Ouchi et al. 2004)

Ouchi et al. (2001)

N=11928 arcmin

• 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.) S

ub-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 (Sekiguch

i et al. 2004)– BVRiz with Subaru/Suprime-Cam (Furus

awa 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)

B V R i’ z’

28.2 27.2 27.6 27.5 26.5

Very Deep + wide-field images

SXDS(1.3 deg2)

[2h18m00s ,-5o00’00”]

~150 Mpc for z=3-6

Comparison of Surveyed Areas: Very Deep Multi-band Surveys (i’~27)

• The best data set for clustering of high-z galaxies

SXDS(1.3 deg2)

GOODS (0.09 deg2)

HUDF(0.002deg2) HDF(0.001deg2)

FDF(0.01deg2)

COSMOS (2deg2; 1/4-1/5 integration in BVRz)

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 deg2 sky )

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

Sky Distribution

z~4 BRi-LBGs (z=3.5-4.5)

Red=brightBlue=intermediateBlack=faint

Gray=masked regions

N=16,920

Sky Distribution

z~5 Viz-LBGs (z=4.2-5.2)

Red=brightBlue=intermediateBlack=faint

Gray=masked regions

N=2,768

Sky Distribution

z~5 Riz-LBGs (z=4.6-5.2)

Red=brightBlue=intermediateBlack=faint

Gray=masked regions

N=1,293

Sky Distribution

z~6 i-dropouts (z=5.6-6.2)

Red=brightBlue=intermediate

Gray=masked regions

N= 133

Sky Distribution

z=3.1 LAEs

yellow=LAEsRed =density contour

Background: Image

N= 332

Sky Distribution

z=5.7 LAEs

yellow=LAEsRed =density contour

Background: Image

N= 515

1. Angular correlation functions of LBGs at z=4

10”=350kpc(comoving)

Close Companions of LBGsExample

i’ band

Close companions

• Many LBGs have (a) close companion(s).

• Npairs~1,385

for 1”<θ<5” 　 i.e, ~10- 40 h70

-1kpc (physical)

→ for more quantitative analysis, we derive the angular correlation function of LBGs at z=4

Definitive Detection of the Transitionfrom One-Halo to Halo-Halo Clustering

1. Small scale excess at θ<~5” →r_vir of dark halos with ~1011-1012 h-1Mo

at z=4

z~4

b=

(ωg/

ωm)1/

2

Dark matter (non-linear model)

Small scale clustering

Large-scale cl

usterin

g

N=16,920

2. Large-scale bias (@8Mpc) = 3 　 → ~1011-1012 h-1Mo

MDH~1011-12Mo

2. Large-scale structures made of Lyα Emitters at z=5.7

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 biasb=3.4 ±1.8 (σ20 =0.4 for r=20Mpc)is comparable to the LBG clustering (b=3-5)

N= 515

Voids

3. Forming cluster candidates at z=5.69 and 5.67

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 1-3x1014Mo?

concentration A

concentration B

Densest concentrations of Lyα Emitters in 1x106

Mpc3

5σ-level excess

Dense Concentrations of LAEs at z=5.7:Facts and Implications

• Facts:– v~150-180 km/s

(→8-10x1012Mo, 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

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 ~1012Mo halo.

2) Large-scale structures made of Lyα Emitters at z=5.7　　 Detection of filamentary structures with 10-40 Mpc scale v

oids (large-scale bias 　 b=3.4 ±1.8) → Early formation of filamentary structures of galaxies3) Forming cluster candidates at z=5.69 and 5.67 Identification of LAE concentrations at z=5.69 and 5.67. Ov

erdensity δ~80, SFR density excess ~ 130 → 　 Intensive galaxy formation takes place at the beginnin

g stage of cluster formation?

Spectroscopic Identification for Spitzer/IRAC-bright LBGs

in the GOODS-N

for the GOODS team

ACS z’ IRAC(ch1/ch2)

Spectroscopic Identification for Most Massive Galaxies at z=3-6

Our on-going Project