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Mapping the Early Universe with Galaxies at z=3-6. Cosmic Web Made of 515 Galaxies at z=5.7. Ouchi et al. 2005 ApJ, 620, L1. Masami Ouchi (Space Telescope Science Institute) - PowerPoint PPT Presentation
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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 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