LBG ｓ at z~5

K. Ohta (Kyoto Univ.)

with

I. Iwata (NAOJ, Okayama)

M. Ando (Kyoto Univ.)

M. Akiyama (NAOJ, Subaru)

N. Tamura (Durham, UK)

K. Aoki (NAOJ, Subaru)

•LBG search at GOODS-N and J0053+1234

fields

•V, I_c, z’ ; z~5 with S-Cam/Subaru

•Highest redshift achieved with two-color

diagram using standard filter system

•Age of 1Gyr and 1Gyr earlier from z~3

Two-color diagram

Resulting UV LF at z~5

•Number density of luminous LBGs does not change so much from z=5 to 3

•Fainter LBGs increase at the later epoch

•Luminosity-dependent evolution?

　　　 However….

•Disagreement among UVLFs at z~4, 5

in a luminous part

Example of UV spectra of z~5 LBGs

Ando et al. 2004

Composite spectrum of z~5 LBGs

(vs z~3 LBG)

Ly alpha EW vs UV luminosity at z~5

Dusty environment in luminous LBGs?

Lack of blue luminous LBGs?

Downsizing of LBGs?•Number density of luminous LBGs does not

change so much from z=5 to 3

•Fainter LBGs at z~3 are late comers?

•Luminous z~5 LBGs in dusty environment?

chemically evolved to some degree?

=> lack of blue luminous ones?

•Luminous z~5 LBGs show larger clustering amp.

luminous LBGs reside in massive DHs?

=> SF started eariler?

Large sample of luminous

LBGs will be obtained from

COSMOS