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