Masami Ouchi (STScI)

Progress of the Wide-Field Deep Surveys for Galaxies at z=3-9

Introduction

Recent results of our z=3-7 LyαEmitter studies

On-going Wide-Field NIR Search for z=7-9 objects

Summary

Overview

(1) Galaxy formation: z>~5 emergence of galaxy halos

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

Why are Studies of z=3-9 Galaxies Important?

Num. density evolution of halos predicted with the ΛCDM model of Sheth&Tormen1999

(2) Reionization:

z~6:Epoch of transition

cluster

galaxy

Reionization & Galaxies

Dijkstra et al. (2007)

Galaxies (black dots) and cosmic HII region (orange) from simulations (Iliev et al. 2006)

Lyα line profiles of galaxies at z=8

Lyα emitting galaxies place constraints on reionization properties

Intrinsic Lyα

absorbed

(1) Lyα Emitters (LAEs)

Identify a redshifted Lyα emission line with a narrow band (NB)

Lyα emitting (~dust-poor) star-forming galaxies.

Kodaira et al. (2003)

Redshift

Lyα

(2) Dropout galaxies

Stanway et al. (2005)

Redshift

Identify a redshifted continuum break (Ly break+GP trough)

UV bright star-forming galaxies

SXDF(1.3 deg2;i=27.0)

[2h18m00s ,-5o00’00”]

5 pointings of Suprime-Cam

SDF(0.2 deg2;i=27.4 )

[13h24m39s ,+27o29’26”]

1 pointing of Suprime-Cam

XMM-Newton 0.5-2 (Ueda+07)

VLA 1.4 GHz (Simpson+06)

X-ray(XMM), UV(GALEX), NIR(UKIRT),IR(Spitzer),Sub-mm(SCUBA+BLAST), Radio(VLA,GMRT)

X-ray to Radio

High-z Galaxy Samples

Lyα Emitter (LAE) SDF SXDF

z=3.1: - 356(41) (NB503<25.3; BVNB 2 colors) z=3.7: - 101(29) (NB570<24.7; BVNB 2 colors) z=4.9: 87(5) - (NB711<26.0; RiNB 2 colors) z=5.7: 89(27) 401(17) (NB816<26.0; RiNB 2 colors+ no flux in BV) z=6.6: 58(19) >106 (NB921<26.0; izNB 2 colors+ no flux in BVR) z=7.0: 2(1) - (NB973<25; zNB 2 colors+ no flux in BVR) 　　　　　　　　　　　 Number in () is the one of spectroscopically identified obje

cts 　　　　　 Thanks to the deep & wide field imaging data, we have obtained ~1,000 LAEs at z

=3-7 (c.f. x10 larger number of LAEs than previous studies)

NB503 NB570 NB711 NB816 NB921

Examples of our LAEs

radio loud AGN z=3.123, f1.4=108±18μJy (Courtesy: Simpson)

LAE with a radio contour

AGNVLA 1.4GHz (>20μJy) XMM (≳5e-16 erg/s/cm2)

~3 (radio) and 2(X-ray)/356 sources at z~3

~1(radio) and 2 (X-ray)/101 sources at z~4

0 radio/X-ray detection at z>5.7

→ 　 AGN : ~1/50 of all LAEs

Star-forming galaxies (1-10 Mo/yr) and possibly some cooling clouds and

fluorescence (Juna Kollmeier’s talk)

z=5.7 LAEs (Ouchi et al. 2005)

Evolution of LyαLuminosity Function

Observed LF→no evol.but fLyαabsorbed by IGM intrinsic LF→ likely evolved

Contrary to UV continuum LF of dropout galaxies (e.g. Lehnert+03, Ouchi+04,Shimasaku+05,Bouwens+06+07)

Numer density of intrinsically bright LAEs increases from z=3.1 to 5.7 emergence of different Lyα

population (incl. PopIII, cooling clouds and/or dust poor) at higher redshifts??

Ouchi et al. in prep

Solid: Obeserved LF 　　　　　　　　　　　 Dash: Intrinsic LF

z=5.7

z=3

z=3

z=3

Discovery of z=6.96 LAE in SDF

Not only the record break, but a scientific value.

Iye et al., 2006, Nature, 443, 186

Nature, Sep 14, 2006

At higher redshit: Lyα Luminosity func.

Observed Lyα LF→ Num. dens. of bright LAE decrea

ses from z=5.7 up to 7.0. (c.f. no evol. from z=3-5.7)

Evolution of IGM neutral fraction?

(Kashikawa+06,Iye+06)and/or Galaxy evolution? (Dijikstra+

06)→Only study of LF cannot resolv

e the problem of reionization

Other physical properties for z=6-7 LAEs??

→HST/Spitzer coordinated observations in 2007-2008 (Egami et al.)

z=5.7

z=5.7

z=5.7

---Beyond z=7---Our On-going Wide-Field Search

Wide-field Search for z>7 Dropouts and LAEs

One (to 4) candidates of z=7-8 faint dropouts are identified in the HUDF. Deep search (J~27) in area (~20arcmin2; Bouwens & Illingworth 2006) .

Very faint “candidates” are found by gravitational lens studies (Richard+06, Stark+07).

No intrinsically-bright candidates of z>7 dropouts/LAEs are found by current searches. It cannot give a constraint on LF. Moreover, no spec conf . →A wide-field search is needed!!

Bouwens & Illingworth (2006)

?

Wide-field MOIRCS search in the GOODS MOIRCS: wide-field NIR camera

of Subaru (FoV=28arcmin2) GOODS-N field (~140 arcmin^2)

Ultra-deep field with 1 FoV (30 hrs each for J and Ks)

= x7 FIRES (Labbe et al. 2003) Deep field with 3 FoVs (5 hrs eac

h for J and Ks) =slightly deeper than ISSAC GOOD

S-S In 2006-2008 (in total ~35 nights

are allocated: Ichikawa/Tokoku,Ouchi et al.). See Kajisawa et al. 2006, Ichikawa

et al. 2007 for deep images of 2006 run.

Courtesy Kajisawa

1/8 cu

tout o

f

MOIRCS F

ield

Imag

e

MOIRCS

Two z-dropout Candidates? From the First-Year (2006) Data

We see two candidates in our field. However, these sources are identified at 3-5 sigma levels. Are they real?? → Spectroscopic follow-up is going on with MOS spec. mode of MOIRCS this spring.

Except for these 2 sources, we have no candidates down to J=26 → constraining LF at z~8.

Ouchi et al. ASPC Ser. in press

MLT stars

model

Constraints on UV luminosity function at z~8Luminosity function (LF) of z~8 dropouts Our z-dropout-search results

give upper limits of LF. Even if two candidates are real,

bright-end LF evolves. → Not only for faint galaxies (Bouwens & Illingworth 2006), but also for bright galaxies, number density (luminosity) of dropout galaxies decreases from z=6 to 8

→hierarchical evol.(if UV mass)∝ Adding 2007-2008 data, we will

obtain robust candidates and/or a stronger constraint on LF.

upper limits (with 0 or2 candidates)

Our search goals

z=8.8 LAEs (NB119 filter ） z=8.8 LAE search with our narro

w-band filter (NB119) centered at 1.19 um (Tokoku/Ouchi et al.) in GOODS.

Observations are being proposed to Subaru.

Unique survey parameters (Depth and volume)

Strong constriant on LF of z~9 LAEs. (never achieved. thanks to MOIRCS’s performance)

Expected number of z=8.8 LAEs f~4e-18 erg/s/cm^2→ we expect ~3.3 LAEs (if no evoluti

on of LF from z~7)

←grav. lens search

Jz’

Model spectrum of z~8 dropouts

NB119

Survey limits of z~9 LAE

Our z=8.8 LAE Searchoptical bands

MOIRCS

DeepLarg

e V

ol.

LAEs at redshift higher than z=8.8. Simulations with realistic OH sky an

d MOIRCS optics (varying central wavelength+band width).

A highest redshift LAE reached by MOIRCS 30 hour exp.

　　→ narrow-band filter for z=10.05 LAE

z=10.05 LAEs (NB134 band ） NB134 band (center 1344nm, band

width19.3nm) will be produced this year. (funded by Carnegie observatories).

Aiming to detect of ~1 z=10 LAE (or constrain the LF at z=10).

N(e

xpec

t）

Higher redshifts with MOIRCS/GOODS search

NB119NB134

Results of Simulations

Introduction

Recent results of our wide-field z=3-7 LyαEmitter studiesWe see no evolution of Luminosity function at z=3-5.7, but decrease from z=5.7-7.0.→ evolution neutral fraction of IGM and/or galaxy evolution at z>6

On-going wide-field NIR search for z=7-9 objects in GOODSOur MOIRCS dropout/LAE search (2006-2008).Constraints on z~8 UV luminosity function (decrease a number and/or luminosity of bright-faint galaxies)→ hierarchical evolution?

Summary

Summary