Dynamical Properties of FDynamical Properties of Forming Galaxiesorming Galaxiesat Redshift at Redshift z > 5z > 5

Yoshi TaniguchiYoshi Taniguchi

Research Center for Research Center for Space & Cosmic EvolutionSpace & Cosmic Evolution

Ehime UniversityEhime University

ZOOZOO of Star-Forming Galaxies of Star-Forming Galaxiesat High Redshiftat High Redshift

LAELAELBGLBGEROERODRGDRGBzKBzKSMGSMG･･････････････

z < 5

z > 5

LAEs vs. LBGsLAEs vs. LBGs

LAE surveysLAE surveys may miss weak Lymay miss weak Lyemitters,emitters, but faint cont. doesn’t matterbut faint cont. doesn’t matter

LBG surveysLBG surveys may miss faint continuum sources,may miss faint continuum sources, but w/ or w/o Lybut w/ or w/o Ly doesn’t matter doesn’t matter

LAEs vs. LBGsLAEs vs. LBGs

LAEs tend to beLAEs tend to be younger (larger EW of Lyyounger (larger EW of Ly)) less massive (fainter UV)less massive (fainter UV) ………… ………….. than LBGsthan LBGsBut,But,

not always !not always !

LAEs vs. LBGsLAEs vs. LBGs

LAEs & LBGs are overlappedLAEs & LBGs are overlappedin many physical properties by definitionin many physical properties by definition

Difference between LAEs & LBGsDifference between LAEs & LBGsas a function of redshift & environas a function of redshift & environ

give us hints to understand give us hints to understand SF history in early universeSF history in early universe

But, ……But, ……

LAE to LBG Ratio @ z ~ 3 – LAE to LBG Ratio @ z ~ 3 – 77

SDF

SDF

(Yamada+05, PASJ, 57, 881; Sumiya+08, in prep.)(Yamada+05, PASJ, 57, 881; Sumiya+08, in prep.)

MAHOROBA-11

z=6 sampleby Dow-Hygelund07

HST/ACS Imaging ofHST/ACS Imaging ofLAEs @ z=5.7 & z=4.9LAEs @ z=5.7 & z=4.9in the in the COSMOSCOSMOS Field Field

Morphology of LAEs Morphology of LAEs

HST Treasury Program(Cycle 12 & 13)Scoville et al.

ACS I814

Subaru Intensive Program(S03B , S04B, S05B,…)

Taniguchi et al.Other optical bands

Cosmic Evolution Survey－　 COSMOS　－

COSMOS-20COSMOS-20

12 IB2 NBNB816NB711

119 LAEs @ z=5.7 in COSMOS119 LAEs @ z=5.7 in COSMOS(Murayama et al. 07, ApJS, 172, 523)(Murayama et al. 07, ApJS, 172, 523)

85 LAEs are imaged w/ACS-F814W 85 LAEs are imaged w/ACS-F814W

● 　 Not imaged w/ACS(34 LAEs)

● Detected w/ACS(47 LAEs)

× Not detected w/ACS(38 LAEs)

● Masked out areas

Half-Light Radius (RHalf-Light Radius (RHLHL))(1”=6 kpc @ z = 5.7)

0.15”

47 LAEs detected w/ACS47 LAEs detected w/ACSCompactCompact ( (RRHLHL <0.15 arcsec) <0.15 arcsec) 24 LAEs24 LAEs　　　　 < < RRHLHL > = 0.11±0.02 arcsec > = 0.11±0.02 arcsecExtendedExtended ( (RRHLHL > 0.15 arcsec) > 0.15 arcsec) 23 LAEs 23 LAEs 21: single 21: single 2: double2: double　　　　 < < RRHLHL > = 0.21±0.06 arcsec > = 0.21±0.06 arcsecALLALL　　　　 < < RRHLHL > = 0.16±0.10 arcsec > = 0.16±0.10 arcsec

CompactCompact

(5”x5” for each panel)

Extended - SingleExtended - Single

Extended - DoubleExtended - Double

=0.94”

=0.36”

Non-detectionNon-detection

What do we see in F814W?What do we see in F814W?ACS I814 vs. S-cam NB816ACS I814 vs. S-cam NB816

No correlation between I814 & NB816 We don’t see Ly emission in I814

● extended● extended-double● extended-sp. confirmed○ compact○ compact-sp. confirmed

What do we see in F814W?What do we see in F814W?

LAE spectrumNB816

What do we see in F814W?What do we see in F814W?

Good correlation between (I814z’) & z’ We see UV continuum (>121.6nm) in I814

● extended● extended-double● extended-sp. confirmed○ compact

Three TopicsThree Topics

1. Size-Magnitude Relation 1. Size-Magnitude Relation

2. Dynamical Structures2. Dynamical Structures Disk-like or Spheroid-like ?Disk-like or Spheroid-like ?

3. Multiple-component LAEs3. Multiple-component LAEs

Size-Magnitude Relation Size-Magnitude Relation @ z~6@ z~6- R- RHLHL vs. z vs. z850 850 mag -mag -

● ● + + ** : LAEs : LAEs ■ ■ + + ▲▲ + + ●●: LBGs: LBGs

LAEs are more compact LAEs are younger than LBGs ?

(Dow-Hygelund+ 07, ApJ, 660, 47)

RRHLHL vs. z850 mag vs. z850 mag for High-z LAEs and LBGsfor High-z LAEs and LBGs

z~6z~6 Bouwens06 i-dropout (UDF, UDF-P, GOODS-N&S)Bouwens06 i-dropout (UDF, UDF-P, GOODS-N&S) Bunker03 1 LAE @ Bunker03 1 LAE @ z z =5.7=5.7 Bunker04 UDF i-dropoutBunker04 UDF i-dropout Stanway04a 3 LAEsStanway04a 3 LAEs Stanway04b 2 LAEs in GOODS-NStanway04b 2 LAEs in GOODS-N Dow-Hygelund07 22 Dow-Hygelund07 22 z z ~6 (UDF&UDF-P)~6 (UDF&UDF-P)z~5z~5 Rhoads05 1 LAE @ Rhoads05 1 LAE @ z z =5.42=5.42 Overzier06 23 V dropouts in RG (Overzier06 23 V dropouts in RG (z z =5.2) field=5.2) fieldz~4z~4 Overzier08 63 g dropouts in RG (Overzier08 63 g dropouts in RG (z z =4.1) field=4.1) field 13 spectroscopic confirmed LAEs13 spectroscopic confirmed LAEs

Little difference in sizes between LAEs & LBGsLittle difference in sizes between LAEs & LBGsLittle redshift evolution from z=6 to 4 ?Little redshift evolution from z=6 to 4 ?

LAE (Red) LBG (Black)

RRHLHL vs z vs z850 850 Relation Relation for High-z LBGs and LAEsfor High-z LBGs and LAEs

HST/ACS Imaging ofHST/ACS Imaging ofLAEs @ z=4.9 LAEs @ z=4.9

in the COSMOS Fieldin the COSMOS Field

79 LAEs @ z=4.9 in COSMOS79 LAEs @ z=4.9 in COSMOS(Shioya et al. 08, ApJ, submitted)(Shioya et al. 08, ApJ, submitted)

61 LAEs are imaged w/ACS-F814W 61 LAEs are imaged w/ACS-F814W

● 　 Not imaged w/ACS(18 LAEs)

● Detected w/ACS(55 LAEs)

× Not detected w/ACS(6 LAEs)

● Masked out areas

LAE (Red) LBG (Black)

RRHLHL vs z vs z850 850 Relation Relation for High-z LBGs and LAEsfor High-z LBGs and LAEs

?

Little difference in sizeLittle difference in size between LAEs & LBGs @ each zbetween LAEs & LBGs @ each z

Size evolution from z=6 to 4 is weakSize evolution from z=6 to 4 is weak although LAEs @ z=6 are slightly although LAEs @ z=6 are slightly smaller than those @ z =4 – 5smaller than those @ z =4 – 5

RRHLHL vs z vs z850850 Relation Relation for High-z LAEs and LBGsfor High-z LAEs and LBGs

Dynamical Structures of the LAEsDynamical Structures of the LAEs@ @ z=5.7z=5.7 in COMSOS in COMSOS

Disk-like or Spheroidal-like ?Disk-like or Spheroidal-like ?

Azimuthally-averaged profileAzimuthally-averaged profile w/ PSF deconvolutionw/ PSF deconvolution (Hathi et al. 08, arXiv:0710.0007)(Hathi et al. 08, arXiv:0710.0007)

RRHLHL=0.08”=0.08” ~480 pc~480 pc Sersic Sersic nn=0.8=0.8

RRHLHL=0.21”=0.21” ~1.3 kpc~1.3 kpcSersic Sersic nn=1.4=1.4

22 LAEs

21 LAEs

< 1kpc for z~5 LAEs

(Pirzkal+06)

Azimuthally Averaged CompositeAzimuthally Averaged Composite (PSF-deconvolved analysis) (PSF-deconvolved analysis)

COMPACT

EXTENDED

1”

Dynamical Structures of LAEs Dynamical Structures of LAEs @ z=5.7 in the COSMOS Field@ z=5.7 in the COSMOS Field

Disk-like or Irregular morphologyDisk-like or Irregular morphology for both compact & extended LAEsfor both compact & extended LAEs

Note thatNote that 40% of bright LBGs @ z=2.5 – 5 40% of bright LBGs @ z=2.5 – 5 show disk-like morphology,show disk-like morphology, but 30% show spheroid-like structuresbut 30% show spheroid-like structures (Ravindranath+06)(Ravindranath+06)

Need systematic analysis of dynamical structures of LBGs & LAEs as a function of z

Multiple-component LAEsMultiple-component LAEsin the COSMOS Fieldin the COSMOS Field

Fraction of multiplesFraction of multiples

2/47 = 4 % @ z = 5.72/47 = 4 % @ z = 5.7

8/55 = 15 % @ z = 4.98/55 = 15 % @ z = 4.9

ZOOZOO of Star-Forming Galaxies of Star-Forming Galaxiesat High Redshiftat High Redshift

LBGLBGLAELAEEROERODRGDRGBzKBzKSMGSMG･･････････････

z < 5

z > 5

SummarySummary

There There must bemust be overlaps in observational pr overlaps in observational properties between LAEs and LBGs operties between LAEs and LBGs by defiby definitionnition..

However, systematic studies of both populHowever, systematic studies of both populations ations as a function of zas a function of z are absolutely n are absolutely necessary to understand ecessary to understand the whole history the whole history of star formation in early universeof star formation in early universe..