1. Dynamical Properties of Forming Galaxies at Redshift z > 5
Yoshi Taniguchi
Research Center for
Space & Cosmic Evolution
Ehime University

2. ZOO of Star-Forming Galaxies at High Redshift
LAE
LBG
ERO
DRG
BzK
SMG
･･･････
z > 5
z < 5

3. LAEs vs. LBGs LAE surveys LBG surveys but w/ or w/o Lya doesn’t matter
 may miss weak Lya emitters,
but faint cont. doesn’t matter
LBG surveys
 may miss faint continuum sources,
but w/ or w/o Lya doesn’t matter

4. LAEs vs. LBGs LAEs tend to be younger (larger EW of Lya)
less massive (fainter UV)
………….
than LBGs
But,
not always !

5. LAEs vs. LBGs But, …… Difference between LAEs & LBGs
LAEs & LBGs are overlapped
in many physical properties by definition
But, ……
Difference between LAEs & LBGs
as a function of redshift & environ
give us hints to understand
SF history in early universe

6. (Yamada+05, PASJ, 57, 881; Sumiya+08, in prep.)
LAE to LBG z ~ 3 – 7
z=6 sample
by Dow-Hygelund07
SDF
SDF
MAHOROBA-11
(Yamada+05, PASJ, 57, 881; Sumiya+08, in prep.)

7. HST/ACS Imaging of LAEs @ z=5. 7 & z=4
HST/ACS Imaging of z=5.7 & z=4.9 in the COSMOS Field  Morphology of LAEs

8. Cosmic Evolution Survey Subaru Intensive Program
HST Treasury Program
(Cycle 12 & 13)
Scoville et al.
ACS I814
Cosmic Evolution Survey
－　COSMOS　－
Subaru Intensive Program
(S03B , S04B, S05B,…)
Taniguchi et al.
Other optical bands

9. COSMOS-20
12 IB
2 NB
NB816
NB711

10. 119 LAEs @ z=5. 7 in COSMOS (Murayama et al
119 z=5.7 in COSMOS (Murayama et al. 07, ApJS, 172, 523)  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

11. Half-Light Radius (RHL)
(1”=6 z = 5.7)
0.15”

12. 47 LAEs detected w/ACS Compact (RHL <0.15 arcsec) 24 LAEs
Extended (RHL > 0.15 arcsec)
23 LAEs
21: single
2: double
　　< RHL > = 0.21±0.06 arcsec
ALL
　　< RHL > = 0.16±0.10 arcsec

13. Compact
(5”x5” for each panel)

14. Extended - Single

15. Extended - Double
D=0.94”
D=0.36”

16. Non-detection

17. What do we see in F814W? ACS I814 vs. S-cam NB816
● extended
● extended-double
● extended-sp. confirmed
○ compact
○ compact-sp. confirmed
No correlation between I814 & NB816
 We don’t see Lya emission in I814

18. What do we see in F814W?
NB816
LAE spectrum

19. What do we see in F814W? Good correlation between (I814z’) & z’
● extended
● extended-double
● extended-sp. confirmed
○ compact
Good correlation between (I814z’) & z’
 We see UV continuum (>121.6nm) in I814

20. Three Topics 1. Size-Magnitude Relation 2. Dynamical Structures
Disk-like or Spheroid-like ?
3. Multiple-component LAEs

21. Size-Magnitude Relation @ z~6 - RHL vs. z850 mag -
● + * : LAEs
■ + ▲ + ●: LBGs
LAEs are more compact 
LAEs are younger
than LBGs ?
(Dow-Hygelund+ 07, ApJ, 660, 47)

22. RHL vs. z850 mag for High-z LAEs and LBGs
Bouwens06 i-dropout (UDF, UDF-P, GOODS-N&S)
Bunker z =5.7
Bunker04 UDF i-dropout
Stanway04a 3 LAEs
Stanway04b 2 LAEs in GOODS-N
Dow-Hygelund z ~6 (UDF&UDF-P)
z~5
Rhoads05 1 z =5.42
Overzier V dropouts in RG (z =5.2) field
z~4
Overzier g dropouts in RG (z =4.1) field
13 spectroscopic confirmed LAEs

23. RHL vs z850 Relation for High-z LBGs and LAEs
LAE (Red) LBG (Black)
Little difference in sizes between LAEs & LBGs
Little redshift evolution from z=6 to 4 ?

24. HST/ACS Imaging of LAEs @ z=4.9 in the COSMOS Field

25. 79 LAEs @ z=4. 9 in COSMOS (Shioya et al
79 z=4.9 in COSMOS (Shioya et al. 08, ApJ, submitted)  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

26. RHL vs z850 Relation for High-z LBGs and LAEs?
LAE (Red) LBG (Black)

28. RHL vs z850 Relation for High-z LAEs and LBGs
Little difference in size
between LAEs & each z
Size evolution from z=6 to 4 is weak
although z=6 are slightly
smaller than z =4 – 5

29. Dynamical Structures of the LAEs @ z=5.7 in COMSOS
Disk-like or Spheroidal-like ?
 Azimuthally-averaged profile
w/ PSF deconvolution
(Hathi et al. 08, arXiv: )

30. Azimuthally Averaged Composite (PSF-deconvolved analysis)
COMPACT
22 LAEs
RHL=0.08”
~480 pc
Sersic n=0.8
RHL=0.21”
~1.3 kpc
Sersic n=1.4 1”
EXTENDED
21 LAEs
< 1kpc for z~5 LAEs
(Pirzkal+06)

31. Dynamical Structures of LAEs @ z=5.7 in the COSMOS Field
Disk-like or Irregular morphology
for both compact & extended LAEs
Note that
40% of bright z=2.5 – 5
show disk-like morphology,
but 30% show spheroid-like structures
(Ravindranath+06)
Need systematic analysis of dynamical structures of
LBGs & LAEs as a function of z

32. Multiple-component LAEs in the COSMOS Field
Fraction of multiples
2/47 = 4 z = 5.7
8/55 = 15 z = 4.9

33. ZOO of Star-Forming Galaxies at High Redshift
LBG
LAE
ERO
DRG
BzK
SMG
･･･････
z > 5
z < 5

34. Summary
There must be overlaps in observational properties between LAEs and LBGs by definition.
However, systematic studies of both populations as a function of z are absolutely necessary to understand the whole history of star formation in early universe.