Deep Surveys for High-z Galaxieswith

Hyper Suprime-Cam

M. Ouchi (OCIW),

K. Shimasaku (U. Tokyo),

H. Furusawa (NAOJ), &

HSC Consortium

≲ ≳

Discovery of the most distant galaxy at z=7 (Iye+06)

Signature of Cosmic Reionization (kashikawa+06,Shimasaku+0

6)

Decrease of UV luminosity function (Ouchi+04,Yoshida+06,cf Iwata+03/7)

First Census of Lya Blobs (Matsuda+04,Saito+06)

Discovery of Large-Scale Struc.& Proto-clusters (Shim

asaku+03,Ouchi+05)

Detection of 1&2 halo terms (Ouchi+05, Kashikawa+06,Hamana+06)

UV bright population for deep Spec. (Ando+04/06/07,Nagao+04/05)

Identification of substructure around High-z clusters (Kodama+01, Nakata

+05,Tanaka+06/07)

Suprime-Cam Image (1 pointing: 918 arcmin2)

HST/ACS(1pointing)

HST/ACS has (had) a superb spatial resolution +sensitivity, but the survey speed, S, for high-z galax

ies is S(Suprime) 10 x S(HST)

HSC Surveys for High-z Galaxies

~800 comoving Mpc at z~6-7

HSC Ultra Deep Survey (UDS)

HSC Deep & Wide Survey (DWS)

Suprime-Cam (1 FoV)

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UDS: Hubble Ultra-Deep Field Science (i~28mag; for 0”.5 sources) in a 2 deg2

and

DWS: Subau/XMM Deep Field Science (i~27) in a 10-20 deg2

HSC

SCx30

M*

HSC

SCNex

pect

（30

hr 1

FoV

)

x30

y

HSC: Powerful for High-z Galaxy Studies

x10x10

Expected number of Lya emitters Expected number of dropout galaxies

Nex

pect

（30

hr 1

FoV

)

Our calculations show the expected numbers of high-z galaxies, N(HSC) and N(SC) are z~3-6 : N(HSC)~ 10xN(SC) due to the large FoV z~7 : N(HSC)~ 30xN(SC) due to the large FoV +high red-sensitivity by Hamamatsu CCDs

Key Sciences of HSC/UDS and DWS

1. Cosmic reionization

2. Statistics of star-forming galaxies at z=3-7.5

3. Identification of forming galaxy candidates

4. Evolution of dwarf galaxies at z=0-1.5

We do not include science with NIR images, because we have not yet selected target fields with NIR data. At this moment, we consi

der data with HSC and follow-up spectroscopy.

Evolution of neutral fraction of IGM (Fan et al. 2006)

1. Cosmic Reionization

z~6: Final stage (GP test;Fan+06) z~11: WMAP3+inst. model(Page+07, Spergel+07)

z~6-11: Transition of IGM status

?

Cosmic reionization predicted by neumerical simulation (Iliev et al. 2006)

Galaxies (blue dots) and ionized bubbles (orange)

Cosmic Reionization Probed with Lya Emitters (LAEs)

Dijkstra et al. (2007)

Lyα line profiles of galaxies at z=8 (Model prediction)

Intrinsic Lyα

absorbed

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McQuinn et al. (2007)

Intrinsic LAE dist.

Obsrvd LAE dist.

Neutral IGM

Ionized IGM

90 M

pc

Neutral hydrogen of IGM is constrained by luminosity evolution and clustering properties of Lya emitters (LAEs)

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Neutral Fraction of IGM with Luminosity Function and Correlation Function of Lya Emitters (LAEs)

LF: L*(z=6.5) ~ 0.6 L*(z=5.7) -> xHI≲0.45 (Kashikawa+06) CF: b~3-4 (preliminary) -> xHI≲0.3 (Ouchi et al. in prep.)Weak constraints by large statistical uncertainties and field variance.With HSC, we will obtain robust measurements of LF and CF of Lya emitterscomplementing deep 21cm observations for HI gas with MWA, LOFAR, and SKA.

?

?

? (Large errors)

LF at z=6.6 from Suprime-Cam data CF at z=6.6 from Suprime-Cam data

Only a handful of z~7 dropout galaxies are identified photomerically (e.g. Bouwens & Illingworth 2006). No UV bright z~7 galaxies with SFRn

o dust >20 Mo/yr whose volume density is as small as 10-6Mpc3

Even in the era of JWST/ELT, such a rare population cannot be found, due to the limitation of survey area.

HSC/UDS+DWS will image an area of 2-20 deg2 down to y~26mag (2-10 x UltraVISTA survey). Determination of the bright-end LF Identification of rare bright galaxies at z~7

that will be ideal targets for spectroscopy with JWST/ELTs.

SFR(Mo/yr)= 30 10 1

UV Luminosity Function at z~7

2. Statistics of star-forming galaxies at z=3-7.5 UV Bright Galaxies at z~7

HST

JWST/ELT

HSC/UDS

HSC/DWS

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Statistics of z≲6 galaxies

Precision measurements of LF and CF Constraining star-forming galaxies with numerical simulation, halo occupat

ion distribution (HODs) and conditional luminosity func. models

z=4 LBG correlation function fit by HOD model (Ouchi+06,Hamana+06)

z=4 Mass-luminosity relation by conditional luminosity func. model (Cooray+06)

　 3. Forming Galaxies (Cooling cloud/PopIII) In the first stage of galaxy formation

Primodial gas become cool and infall into the center of dark halo with cooling radiation (cooling cloud)→ spatially-extended strong Lya emission and weak HeIIλ1640.

Massive star-formation from primodial gas with flat IMF (popIII)→ strong Lya and weak HeIIλ1640

The first stage of galaxy formation is characterized by strong Lya and weak HeII We should search for strong Lya emitters （ wit

h a large EW), and find forming galaxies Any candidates of forming galaxies at z~3-7.

5? Theoretical models predict A bright cooling cloud with HeIIλ1640 can be fo

und in a volume of ~105 Mpc3 at z~2-3(Yang et al. 2006) .

At z=5, ~1/1000 of cosmic SFR is constibuted by popIII (Trac & Cen 2006)

cooling clouds predicted by numerical simulations (Yang et al. 2006)

Lyα

HeII λ1640

Candidates of forming galaxies??

Ouchi et al. (2007)

Cannot be explained by ordinary SF (Salpeter IMF)

(Matsuda et al. 2004)

Lya blobs at z=3 (size~30-200 kpc)

Large Lya EW objects including Lya blobs and compact Lya emitters （ e.g. Matsuda+04, Saito+06, Nilsson+06 ）

We see no HeII emission line originated from cooling clouds or popIII (e.g. Dawson+04,Nagao+06,Ouchi+07, c.f. Jemenez+06)

EW distribution of Lya emitters

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Wide-field+high sensitivity are key Small number density （ cooling

cloud~10-5 Mpc, popIII is less than that? ）

HSC data are appropriate Supply the targets to JWST a

nd TMT for identifying HeII by spectroscopy Distinguish with HeII from AGN u

sing CIV1549 （ +X-ray data) Distinguish with HeII from WR-st

ars using the line width (<1000km/s)

Saito et al. 2006

Volume limit of SPCAM search

Cooling Cloud+PopIII Search with HSC

4. Evolution of dwarf galaxies at z=0-1.5

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Luminosity function of z=1 galaxies in the HUDF

Statistics of high-z dwarf galaxies (halo mass from clustering, stellar mass etc.) and characterize building blocks. (spectroscopic follow-up with JWST+TMT)

Survey Designs of HSC/UDS and DWS

Key Sciences of HSC Deep Surveys 1. Cosmic reionization 2. Statistics of star-forming galaxies at z=3-7.5 3. Wide-field search for forming galaxies 4. Evolution of dwarf galaxies at z=0-1.5

(See the HSC white paper for more details)

Your ideas, discussions, and participation are needed!!

Summary