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最近の z~7-8 LBG 探査. 2009 年 10 月 28 日 鍛治澤 賢. 最近の z~7-8 LBG 探査の論文紹介. Bouwens et al. 2009 arXiv:0909.1803 --- Y-dropout UVLF Oesch et al. 2009 arXiv:0909.1806 --- z-dropout UVLF Bunker et al. 2009 arXiv:0909.2255 --- z-dropout UVLF McLure et al. 2009 arXiv:0909.2437 --- photo-z SED fitting

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最近の z~7-8 LBG 探査

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Z 7 8 lbg

最近の z~7-8 LBG探査

2009年10月28日

鍛治澤 賢


Z 7 8 lbg1

最近のz~7-8 LBG探査の論文紹介

Bouwens et al. 2009 arXiv:0909.1803 --- Y-dropout UVLF

Oesch et al. 2009 arXiv:0909.1806 --- z-dropout UVLF

Bunker et al. 2009 arXiv:0909.2255 --- z-dropout UVLF

McLure et al. 2009 arXiv:0909.2437 --- photo-z SED fitting

Labbe et al. 2009 arXiv:0910.0838 --- +IRAC stellar mass

Oesch et al. 2009 arXiv:0909.5183 --- morphology

Wilkins et al. 2009 arXiv:0910.1098 --- z-dropout

Castellano et al. 2009 arXiv:0909.2853 --- z-dropout

Hickey et al. 2009 arXiv:0909.4205 --- Y&z-dropout

Ouchi et al. 2009 arXiv:0908.3191 --- z-dropout

HUDF: HST/WFC3

GOODS-S: HST/WFC3

GOODS-S: VLT/HAWK-I

SDF & GOODS-N: Subaru/Suprime-Cam

COSMOS: UKIRT/WFCAM & CFHT/WIRCAM

Capak et al. 2009 arXiv:0910.0444 --- z-dropout


Lyman break feature

Lyman break feature

Lyman

break


Z 7 8 lbg

z=0.5

z=1.0

z=1.5

z=3.0


Lyman break galaxies

Lyman Break Galaxies

U-dropout

z~3

G-dropout

z~4


Previous studies of z 7 lbgs

Previous studies of z~7 LBGs

Bouwens et al. 2008

HST/NICMOS J&H-bands data limiting mag. ~26.5-28ABmag


Z 7 8 lbg2

最近のz~7-8 LBG探査の論文紹介

Bouwens et al. 2009 arXiv:0909.1803 --- Y-dropout UVLF

Oesch et al. 2009 arXiv:0909.1806 --- z-dropout UVLF

Bunker et al. 2009 arXiv:0909.2255 --- z-dropout UVLF

McLure et al. 2009 arXiv:0909.2437 --- photo-z SED fitting

Labbe et al. 2009 arXiv:0910.0838 --- +IRAC stellar mass

Oesch et al. 2009 arXiv:0909.5183 --- morphology

Wilkins et al. 2009 arXiv:0910.1098 --- z-dropout

Castellano et al. 2009 arXiv:0909.2853 --- z-dropout

Hickey et al. 2009 arXiv:0909.4205 --- Y&z-dropout

Ouchi et al. 2009 arXiv:0908.3191 --- z-dropout

HUDF: HST/WFC3

GOODS-S: HST/WFC3

GOODS-S: VLT/HAWK-I

SDF & GOODS-N: Subaru/Suprime-Cam

COSMOS: UKIRT/WFCAM & CFHT/WIRCAM

Capak et al. 2009 arXiv:0910.0444 --- z-dropout


Bouwens et al arxiv 09091803

Bouwens et al. arXiv:09091803

Hubble Ultra Deep Field

HST/ACS z-band image

HST/WFC3

Y, J, H-bands

Ultra deep HST/ACS optical images

VLT/ISAAC

Magellan/PANIC

Ks-band

HST/NICMOS

J&H-bands

McLure et al.

HUDFHST/WFC3 による Y-dropout 探査


Hst wfc3

HST/WFC3

WFC3 instrumental handbook


Hst wfc31

HST/WFC3

WFC3 instrumental handbook


Bouwens et al arxiv 090918031

Bouwens et al. arXiv:09091803

HUDF09 program first epoch data

(August 26 ~ September 6, 2009)

F105W (Y) --- 16 orbits

F125W (J) --- 16 orbits

F160W (H) --- 28 orbits

(1 orbit ~ 40min)

~ 4.7 arcmin2

(two UDF05 fields will be also observed in 2010)

PSF FWHM ~ 0.2”

5σ limit @ 0.4” diameter ~ 29ABmag

  • HST/ACS data

B, V, i, z -bands ~29-29.5ABmag

HST/WFC3 data


Bouwens et al arxiv 090918032

Bouwens et al. arXiv:09091803

  • Source detection

  • Color selection

J + H combined image

>5.5σ in J band

  • Y-J > 0.8

  • J-H < 0.5

  • J-H < 0.2 + 0.12×(Y-J)

  • no detection (<2σ) in B,V,i,z

(those with 1.5~2σ detection in more

than one optical band were rejected)

Y-dropout selection


Bouwens et al arxiv 090918033

Bouwens et al. arXiv:09091803

5 candidates

blue J-H color

(UV slope β<~-2.5)

Possible contaminants

>5σ in J & >4σ in H

All WFC3 data were obrained in 12days

brown dwarfs are more bluer and rare

Simulation with 24.5~26mag objects

 Not spurious objects

 Not SNe

 Not galactic stars

the expected number of, contaminants

by photometric scatter is very small (<~0.2)

selected z~8 candnoidates


Bouwens et al arxiv 090918034

Bouwens et al. arXiv:09091803

5 candidates

blue J-H color

(UV slope β<~-2.5)

H~28.2-29.2 mag

half light radius ~ 0.15”

(~PSF)

(~0.7h-1kpc @z~8)

selected z~8 candidates


Bouwens et al arxiv 090918035

Bouwens et al. arXiv:09091803

Expected number for no LF evolution

  • (1+z)-1 size evolution from z~4

  • UV slope β=-2.5±0.4

  • are assumed.

z~6 i-dropout LF  24 Y-dropouts

z~7 z-dropout LF  11 Y-dropouts

(~70% statistical error

~35% field-to-field variance)

Observed number is lower (~1σ level)

Number counts


Bouwens et al arxiv 090918036

Bouwens et al. arXiv:09091803

Extraoplation of UV LF at z<7 to z~8

 M*UV~-19.45, φ*~0.0011Mpc-3, α~-1.74

good agreement with the observed results

Fit M*UV with the observed data

φ*~0.0011Mpc-3, α~-1.74 are assumed

M*UV = -19.3±0.3

M*UV = -20.2±0.2 @z~6

M*UV = -21 @z~4

 strong evolution of M* (?)

Stepwise LF

 weak evolution at -19~-18 mag

Evolution of UV LF


Bouwens et al arxiv 090918037

Bouwens et al. arXiv:09091803

Integrate the stepwise UV LF

 UV luminosity density

unobscured SFR density

(and dust correction with those

estimated at z~5-6 )

SFR density at z~8


Mclure et al arxiv 0909 2437

McLure et al. arXiv:0909.2437

  • HST/WFC3

  • HST/ACS

  • Spizter/IRAC

HST/ACS z-band image

Bouwens et al. と同じデータを独立に処理

PSF FWHM ~ 0.15”(Y), 0.16”(J), 0.18”(H)

HST/WFC3

Y, J, H-bands

5σ limit @0.4” diameter ~29ABmag

5σ limit @0.6” diameter ~29mag

(~28mag for z-band)

VLT/ISAAC

Magellan/PANIC

Ks-band

5σ limit ~25.9(3.6μm)

25.5(4.5μm)

23.3(5.8μm)

22.9(8.0μm)

HST/NICMOS

J&H-bands

McLure et al.

z~6-9 galaxy search with HUDF HST/WFC3


Mclure et al arxiv 0909 24371

McLure et al. arXiv:0909.2437

  • Source detection

  • Photometric redshift

  • >[email protected] detection in at least one of YJH-bands

  • No detection (2σ) in i-band

 300 objects

BVizYJH-bands + 3.6 & 4.5μm

upper limit

Charlot & Bruzal 2007 templates

+ empirical U-dropout spectra

〇: z>7 candidates

  • χ2 distribution z>5.9 candidates

Sample selection

 49 candidates


Mclure et al arxiv 0909 24372

McLure et al. arXiv:0909.2437

example

z

Y

J

H

  • Photometric redshift

Charlot & Bruzual 2007 templates

+ empirical U-dropout spectra

τ=0.1~10Gyr

Calzetti extinction

Av=0~2mag

1 solar metallicity

Salpeter IMF

  • χ2 distribution z>5.9 candidates

 49 candidates

Sample selection


Mclure et al arxiv 0909 24373

McLure et al. arXiv:0909.2437

SED

magnitude

χ2 distribution

 visual check

spurious artifact

Transient object

Contamination by T dwarfs

  • ~0.5 down to z=29ABmag

  • in 4.5arcmin2 WFC3 field

The brightest candidate  SN or other transient soruce

(not detected at all

in NICMOS images)

Sample selection


Mclure et al arxiv 0909 24374

McLure et al. arXiv:0909.2437

49 z>6 candidates

No detection in i-band

 incomplete at 5.9<z<6.25

including

15 out of 16 z-dropouts in Oesch et al.

all 5 Y-dropouts in Bouwens et al.

+ additional 15 z>6.25 candidates

The faintest z-dropout candidate in Oesch et al.

Selected sample


Mclure et al arxiv 0909 24375

McLure et al. arXiv:0909.2437

15 z>7 candidates

8 z>7.5 candidates

3 z>8 candidates

J~28-29mag

Including 5 Y-dropouts in Bouwens et al.

these 5 have acceptable secondary peak at z~1.6

4 z>7.8 candidates occur in two pairs

〇: z>7 candidates

extremely high-z sample


Mclure et al arxiv 0909 24376

McLure et al. arXiv:0909.2437

15 z>7 candidates

8 z>7.5 candidates

3 z>8 candidates

J~28-29mag

Including 5 Y-dropouts in Bouwens et al.

these 5 have acceptable secondary peak at z~1.6

4 z>7.8 candidates occur in two pairs

extremely high-z sample


Mclure et al arxiv 0909 24377

McLure et al. arXiv:0909.2437

15 z>7 candidates

8 z>7.5 candidates

3 z>8 candidates

J~28-29mag

Including 5 Y-dropouts in Bouwens et al.

these 5 have acceptable secondary peak at z~1.6

4 z>7.8 candidates occur in two pairs

For the faintest candidates (J, H ~29),

no detection in optical ACS images is

not sufficient to pick up Lyman break

exclusively.

extremely high-z sample


Mclure et al arxiv 0909 24378

McLure et al. arXiv:0909.2437

redshift probability distribution

+

1/Vmax method

6.5<z<7.5

z~7 UVLF

z~8 UVLF

  • similar shape with z~6 UVLF

  • number density evolution of

  • a factor of ~2.5 from z~6

M*1500 ~ -20.11

Φ* ~ 0.0007Mpc-3

α ~-1.72

  • cannot constrain the shape of UVLF

  • Number density at M1500~-19.5 is a factor of ~2

  • smaller than at z~7

7.5<z<8.5

UV luminosity function


Castellano et al arxiv 0909 2583

Castellano et al. arXiv:0909.2583

Great Observatories Origins Deep Survey - South

  • deep HST/ACS optical images

  • deep Spizter/IRAC MIR images

  • deep VLT/ISAAC NIR images

  • Chandra

  • Spitzer/MIPS

z-dropout search in GOODS-S with HAWK-I


Castellano et al arxiv 0909 25831

Castellano et al. arXiv:0909.2583

HAWK-I 7.5’ x 7.5’ F.O.V 0.106”/pix

Y-band 2 pointings

Science Verification & ESO Large Program

GOODS1 --- 16.25 hour 0.514” FWHM

GOODS2 --- 16.93 hour 0.489” FWHM

~89.7arcmin2 ~100% complete at Y~26.2

~30%compete at Y~26.8

spurious source negligible at Y<26.5

~10% at Y~26.8

Multi-wavelength data

1σ limit

VLT/VIMOS U, R-bands (29.1, 29.5)

HST/ACS B, V, i, z-bands(29.0, 29.1,28.6,28.2)

VLT/ISAAC J, H, K-bands (26.6,26.2,26.2)

VLT/HAWK-I data


Castellano et al arxiv 0909 25832

Castellano et al. arXiv:0909.2583

Y-selected Y<26.7

Y-J>1.0

detect z>6.5 Lyαbreak

HAWK-I

Y-band

ACS z-band

sample selection


Castellano et al arxiv 0909 25833

Castellano et al. arXiv:0909.2583

Y-selected Y<26.7

Y-J>1.0

Y-J<1.5 & Y-K<2.0

detect z>6.5 Lyαbreak

reject old/dusty galaxies at z~1-4

sample selection


Castellano et al arxiv 0909 25834

Castellano et al. arXiv:0909.2583

Y-selected Y<26.7

Y-J>1.0

Y-J<1.5 & Y-K<2.0

No detection in optical

detect z>6.5 Lyαbreak

reject old/dusty galaxies at z~1-4

<2σ in all UBVRI-bands

<1σ in at least four of UBVRI-bands

139  9 candidates

One of interlopers with z-Y>1

sample selection


Castellano et al arxiv 0909 25835

Castellano et al. arXiv:0909.2583

add artificial objects with Y=24-27.5 at z=5.5-8

(assuming size and LF of z~5.5-6 LBGs)

Simulation for sample selection


Castellano et al arxiv 0909 25836

Castellano et al. arXiv:0909.2583

9 z~7 candidates

1 known cool dwarf is rejected

(relatively red Y-J color)

expected contamination  ~3.4 cool dwarfs

for 2 HAWK-I F.O.V.

another one which is not detected in the

deep NICMOS H-band (Y-H<-1) is rejected

 7 candidates

Selected candidates


Castellano et al arxiv 0909 25837

Castellano et al. arXiv:0909.2583

B+V+i

z

Y

J+H+K

F110W

F160W

3.6μm


Castellano et al arxiv 0909 25838

Castellano et al. arXiv:0909.2583

stacking of 7 candidates

 zphot=6.80

Selected candidates


Castellano et al arxiv 0909 25839

Castellano et al. arXiv:0909.2583

Observed number counts of z~6.8 LBGs

are smaller than predictions from z~6 LFs.

(No evolution for UV LF

between z~6 and z~6.8)

  • UV LF seems to evolve

  • between z~6 and z~6.8

Number Counts


Castellano et al arxiv 0909 258310

Castellano et al. arXiv:0909.2583

Assumed UV Luminosity function

simulation

(source detection, color selection)

Expected z-dropout number counts

Observed number counts

Maximum likelihood

Φ* = 0.35+0.16-0.11 ×10-3 Mpc-3

M*(1500Å) = -20.24±0.45

assuming α=-1.71

UV luminosity function


Castellano et al arxiv 0909 258311

Castellano et al. arXiv:0909.2583

Φ* = 0.35+0.16-0.11 ×10-3 Mpc-3

M*(1500Å) = -20.24±0.45

assuming α=-1.71

Evolution between

z~6 and z~6.8

d(logΦ*)/dz = -0.59±0.25

dM*/dz = 0.13±0.51

rule out no evolution between z~6 and z~6.8

at 99% confidence level

UV luminosity density

ρUV = 1.5+2.0-0.9×1025 erg/s/Hz/Mpc3

 a factor of ~3.5 lower than at z~6

Evolution of UV LF


Ouchi et al arxiv 0908 3191

Ouchi et al. arXiv:0908.3191

GOODS-North

Subaru Deep Field

z-dropout search in SDF & GOODS-N with Subaru/S-Cam


Ouchi et al arxiv 0908 31911

Ouchi et al. arXiv:0908.3191

y (zR)-band 2 fields --- 1568 arcmin2

Subaru Deep Field 26 hours 810 arcmin2

GOODS-North 33 hours 758 arcmin2

3σ limit @ 1.8” diameter SDF 26.4 ABmag

GOODS-N 26.2 ABmag

Other bands

SDF BVR + z’

GOODS-N UBVR + z’

z-band 3σ limit SDF 27.7 mag

GOODS-N 26.9 mag

Suprime-Cam data


Ouchi et al arxiv 0908 31912

Ouchi et al. arXiv:0908.3191

  • y-selected samaple

>4σ limit SDF y<26.1

GOODS-N y<25.9

  • z’-y > 1.5

selection for z>6.5 galaxies

possible contamination by cool dwarfs

(no selection by Y-J color)

  • no detection in UBVR-bands (<2σ)

<2σ limit SDF 29.4(B), 28.6(V), 28.8(R)

GOODS-N 27.3(U), 28.0(B), 26.7(V), 27.0(R)

Sample selection


Ouchi et al arxiv 0908 31913

Ouchi et al. arXiv:0908.3191

15+7=22 candidates

all candidates have y>25.4mag

1 (brightest) candidate  zspec=6.96

Selected candidates

GOODS-N

SDF


Ouchi et al arxiv 0908 31914

Ouchi et al. arXiv:0908.3191

detection completeness [email protected]=25.5

>[email protected]~25.8

Selected candidates


Ouchi et al arxiv 0908 31915

Ouchi et al. arXiv:0908.3191

22 candidates

Expected contamination

~1 spurious source

~0.1 transient object

~1 lower-z galaxies with photometric error

~8 L/T-type dwarfs

redshift selection function

UV luminosity function

signifincantly decreases from z~6

at bright magnitude

UV luminosity fobunction


Ouchi et al arxiv 0908 31916

Ouchi et al. arXiv:0908.3191

Subaru/Scam + HST/NICMOS

Φ* = 1.10+2.79-0.79×10-3 Mpc-3

M* = -19.9±0.7

α = -1.66±1.32

Evolution between z~6 and z~7

at >2σ level

The decrease of L* is dominant factor ?

UV luminosity function


Ouchi et al arxiv 0908 31917

Ouchi et al. arXiv:0908.3191

integrating UV LF

2.7+6.9-1.9×1026 erg/s/Hz/Mpc3

SFR density

3.4+8.6-2.4×10-3 M◎/yr/Mpc3

evolution of a factor of >10

between z~2-3 and z~7

SFRD decreases even from z~6 to z~7.

UV luminosity density


Ouchi et al arxiv 0908 31918

Ouchi et al. arXiv:0908.3191

strong clustering of z~7 LBGs

especially for UV bright LBGs

Spatial distribution


Summary

Summary

UV luminosity density

(LBG number density)

factor of 2~3.5

decrease

factor of 2~3

decrease

z~6

(i-dropout)

z~7

(z-dropout)

z~8

(Y-dropout)


Z 7 8 lbg

おまけ


Oesch et al arxiv 0909 5183

Oesch et al. arXiv:0909.5183

Size evolution

Surface SFR density


Labbe et al arxiv 0910 0838

Labbe et al. arXiv:0910.0838

Stacking analysis with IRAC data

Stellar mass of z&Y-dropouts

Evolution of stellar mass density


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