Masami Ouchi (STScI)for the SXDS Collaboration

Cosmic Web Made of 515 Galaxies at z=5.7

Ouchi et al. 2005ApJ, 620, L1

Perspectives from the Subaru Wide-Field Deep Survey-- Suprime-Cam+FOCAS to HySuprime+WFMOS --

Overview

• 1. Highlight clustering results ofour on-going wide-field deepsurvey with Suprime-Cam +FOCAS– Angular correlation of LBGs at z=3-6

– Large-scale structures/clusters ofLAEs at z=5.7

• 2. Future Prospects for the surveywith HyperSuprime + WFMOS

8m-SUBARU

Suprime-Cam

• A multi-wavelength data– 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

– BVRiz with Subaru/Suprime-Cam(Furusawa et al. in prep)~5hr/band/pointing

– NB530, NB570=25.0, NB816=26.0,– NB921~25.5 (50% done)– Subaru/FOCAS (Akiyama et al. in Prep.)– VLT/VIMOS (Simpson/ Saito et al. in prep)

Subaru/XMM Deep Survey (SXDS) Field

26.527.527.627.228.2

z’i’RVBVery Deep + wide-field data

SXDS(1.3 deg2)

[2h18m00s ,-5o00’00”]

~150 Mpc at z=3-6

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

• Appropriate data for clustering of high-z galaxies

SXDS(1.3 deg2)

GOODS (0.09 deg2)

HUDF(0.002deg2) HDF(0.001deg2)

FDF(0.01deg2)

COSMOS →complimentary data(2deg2; but ~1/4 exp. time in BVRz)

High-z Galaxy Samples

• Lyman Break Galaxy (LBG or dropouts)– 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; i-z>2 + no flux in B,V,R)

• Lyα Emitter (LAE)– z=3.1: 356 (NB503<25.3; BVNB 2 colors)– z=3.7: 101 (NB570<24.7; BVNB 2 colors)– z=5.7: 515 (NB816<26.0; RiNB 2 colors+ no flux in BV)– z=6.6: --- 50% of data obtained this fall --- (Goal: 5xSDF)

• Thanks to the deep & wide field imaging data, we haveobtained ~20,000 LBGs and ~1,000 LAEs at z=3.5-6.2 (6.6)(~x10 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 inthese samples arespectroscopicallyconfirmed.

e.g.– 19/515 for z=5.7 LAEs

spectroscopic obs. continue

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 Lyα Emitters

Red=brightBlue=intermediate

Gray=masked regions

Sky Distribution

z~4 Lyα Emitters

Red=brightBlue=intermediate

Gray=masked regions

Sky Distribution

z~6 Lyα Emitters

Red=brightBlue=intermediate

Gray=masked regions

10”=70kpc(physical)

Close Companionsz=4 LBGs : example

i’ band

i ) Angular Correlation Functionsof LBGs at z=4-6

Dark Matter

Angular Correlation Function of z=4 LBGs

Dark Matter

Angular Correlation Function of z=4 LBGs

Dark Matter

Angular Correlation Function of z=4 LBGs

Dark Matter

Angular Correlation Function of z=4 LBGs

Dark Matter

Angular Correlation Function of z=4 LBGs

Definitive Identification of the Transitionbetween Small and Large Scale Clustering

Dark matter

Small scale clustering

Large-scale cl

usterin

g

2. Large-scale bias(@8Mpc) = 3　→ ~1011-12 h-1Mo

MDH~1011-12Mo

Ouchi et al. 2005, submitted to ApJ(astro-ph/0508083)

N=16,920z~41. Small scale

excess at θ<~7”→r_vir of dark halos with~1011-12 h-1Mo

Approach to Dark Side of Galaxy Formation

Fitting the CDM model toω(θ)　and number density

z=4 z=5

z=6

Mass of Hosting Dark HalosAnd their evolution at z=4-6

Muv (AB)

• Hosting halo massdecreases from z=4 to 6.

… what does it mean??→ UV luminosity (SFR)

increases at higher-z for thegiven hosting halo mass.

• Active star-formation can betriggered in less massivehalos at earlier epoch→This may explain the ”anti-hierarchical behavior of starformation history ?(i.e.Numerous less massivehalos finish convert gas intostars at early epoch.)

-19 -20 -21 -22

~SFR

z=4z=5z=6

bright

ii ) Clustering of Lyα Emitters at z=5.7

Sky Distribution of Lyα Emittersshows individual structures

z=4 z=5observer

z=3

• For LBGs, individual clustering properties areerased by the wide-redshift selection window(Δz~1 → 400Mpc: 2D distribution)

• Lyα Emitters (LAEs) are selected in a slice ofuniverse (Δz~0.1 → 40Mpc: 2.5D distribution)Ideal for studying properties of individual structures

↓LBG selection (Δz=1)Narrow-band selection(Δz<0.1) ↓

Large-Scale Structures at z=5.7

Ouchi et al. 2005, ApJ, 620, L1

z=5.7±0.05

~40Mpcin lineof sight

- Galaxy concentrationsconnected withfilaments

-10-40 Mpc scale voids

Large-scale structuresof LAEs are qualitativelysimilar to those ofpresent-day Universe.

→Very early formationof filamentary LSSsmade of galaxies

The large-scale biasb=3.4 ±1.8is comparable to theLBG clustering (b=3-5)

N= 515

Voids

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 thesuveyed comoving volume→ Progenitors of massive cluster with 1-3x1014Mo?

concentration A

concentration B

Densest concentrationsof Lyα Emitters in

1x106Mpc3

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, thebeginning stage of formation ofcluster/cluster core whosemembers will becomesubsequently old ellipticals→Forming cluster candidates

– Intensive galaxy formationtakes place at a specific placeof the high-z Universe? →Significant contribution toreionization??

Close-up view of the concentration A

SXDF/FCC-A: Forming Cluster Candidateat z=5.69

1 Mpc at z=5.69

Future Prospects for the Surveywith HySuprime & WFMOS

Precision Measurements ofCorrelation Function

• For very high-z galaxies(z>5), more accuracy forsmall-scale CF→ Galaxydistribution follow the haloprofile? (e.g. NFW for high-zgalaxy distribution??)

• HySPCAM+WFMOS→profile + DH mass

• Where galaxy formation istriggered in a DH?

High-z Star-FormaingCluster Search

1/Vs

z=0

z=6

Mass function

• A few high-z clusters made of SF galaxies are found.• HySPCAM+WFMOS→ A number of high-z clusters with mass.• Mass function of SF galaxy clusters→ cluster evolution

Luminosity Function of High-z GalaxiesColor Selected Sample (LBG) v.s. Spectroscopic Sample

Le Fevre et al. 2005

Color selectionmisses galaxiesby a factor of twoor more??

• We may miss a largefraction of high-z galaxieswith a color-selectedsample ← Classicalmagnitude-limitspectroscopic survey (LeFevre et al. 2005).

• WFMOS + HySPCAM →rough pre-selection withcolor→　magnitude-limitlike spectroscopic surveyfor high-z galaxies

• Conclude luminosityfunction at z=3-7

Narrow-band selectedz=3.1±0.03 objects for

BAO survey??

1 hour(5σ) for NB imaging~1 hour for spectroscopy

Pros:• Success rate of spectroscopy

~100% with Lyα by ~1 hour exp.

Cons:• NB=25.0 (5σ: 1 hr) →Σ= 200 objects/deg2

(Not dense enough for WFMOS)Redshifts of Lyα may be messy ).

Ouchi et al. in prep

Extended Lyα Sources

• Extended Lyα Sources (cooling cloud??) are quite rare (n~10-5Mpc).• HySPCAM (+WFMOS) → Statistical number of extended Lyα sources.• Unveiling the nature of extended Lyα sources with a statistical number of sample

Saito et al., 2005, Submitted to ApJ(in SXDS field)

Un, NB497, NBcorr, BV, R

Matsuda et al. 2004, ApJ, 128, 569SSA22 field (in Steidel’s z=3.1 cluster)

Volume limit of SPCAM search

Summary1. Highlight some results of our on-going wide-field deep survey

– Angular correlation of LBGsDefinitive detection of small & large-scale clustering→　multiple LBGs residing in a ~1011-12Mo halo. Hosting Halo mass decreases from z=4 to 6. → Active star-formation can be triggerd in less massive halos at earlier epoch?

– Large-scale strucutres of LAEsDetection of filamentary structures with 10-40 Mpc scale voids (large-scale bias　b=3.4 ±1.8) → Early formation of filamentary structures of galaxies

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? →Significantcontribution to reionization??

2. Future Prospects for the survey with HyperSuprime + WFMOS - CF of high-z galaxies→Relation between galaxy formation and structure

formation (DH). - High-z star-forming cluster search→ Cluster evolution - Precise Luminosity functions with spectroscopic sample→ Most basic

measurements to understand galaxy formation - Systematic extended Lyα source search → Nature of unknown objects