Culling Kband Luminous Massive Star Forming Galaxies at

Culling K-band Luminous, Massive Star Forming Galaxies at z>2 N. ARIMOTO (NAOJ) X. Kong, M. Onodera, C. Ikuta (NAOJ), K. Ohta (Kyoto), N. Tamura (Durham), A. Renzini, E. Daddi (ESO), A. Cimatti (Arcetri), T. Broadhurst (Tel’Aviv)

Formation of Giant Ellipticals Massive elliptical galaxies are the products of recent hierarchical merging of pre-existing disk galaxies taking place largely at z<1. 5 with moderate SFRs (eg, Cole et al. 2000). Near IR wide field imaging is crucial. Fully assembled massive galaxies with Evolution Mass Function (Baugh et al. 2002) Ms>1011 Mo at z>2 are extremely rare.

Previous NIR Image Surveys 1. 2. 3. 4. 5. 6. Hubble Deep Field North & South 2 x 5. 3 arcmin 2 K 20 (NTT) 52 arcmin 2 Subaru Deep Field (Ks=22. 6) 4 arcmin 2 Subaru XMM Deep Field (Ks=22. 1) 114 arcmin 2 Goods (HDF-N & CDF-S) 160 arcmin 2 Hubble Ultra Deep Field (NICMOS) 5. 8 arcmin 2 7. EIS 3 a-F (Subaru/VLT, Ks=20. 8) 8. Daddi-F (Subaru/VLT, Ks=19. 0) 900 arcmin 2

Subaru/Sup-Cam Observation ESO Imaging Survey (EIS Deep 3 a) Field RA=11: 24: 50, DEC=-21: 42: 00 (J 2000. 0) Subaru/Suprime-Cam BRIz’: 2003/03/02 -04 NTT/SOFI JK : 2002/03/28 -31 BRIz’ (900 arcmin^2) 3σ in 2”(AB) B(AB)=27. 46 R(AB)=26. 87 I(AB)=26. 56 z’(AB)=26. 07 JK (500, 380 arcmin^2) 3σ in 2”(AB) J(AB)=23. 40, Ks(AB)=22. 70

Subaru/Sup-Cam Observation Daddi Field RA=14: 49: 29, DEC=09: 00 (J 2000. 0) Subaru/Suprime-Cam BIz’: 2003/03/02 -04 WHT R : 1998/03/19 -21 NTT/SOFI K : 1999/03/27 -30 BRIz’ (900 arcmin^2) 3σ in 2”(AB) B(AB)=26. 59 R(AB)=25. 64 I(AB)=25. 62 z’(AB)=25. 31 K (715 arcmin^2) 3σ in 2”(AB) Ks(AB)=20. 91

K-band Galaxy Number Counts

K-selected High-z Galaxies 1. Extremely Red Objects (EROs) Mc. Carthey et al (1992) R-K>5. 0, I-K>4. 0, z>1. 0, Old Passive & Dusty Star-Forming Galaxies 2. Distant Red Galaxies (DRGs) Frank et al. (2003) J-K>2. 3, z>2 780 EROs in Deep 3 a-F 380 EROs in Daddi-F 240 DRGs in Deep 3 a-F

New Galaxy Population (Bz. Ks) Daddi et al. (2005): Bz. K=(z-K)AB-(B-z)AB>-0. 2

BK 20=BEIS z. K 20=z. EIS-0. 16

High-z galaxies in our fields Star-forming galaxies at z>1. 4 (Bz. Ks) Old galaxies at z>1. 4: PEGs Bz. Ks stars 425 Bz. K in Deep 3 a 145 Bz. K in Daddi-F

B R I z’ J K

Bz. K(ERO) ERO Bz. K ERO

Z=1. 5564 ＣＩＶ VLT Observation of ～ 300 Bz. K galaxies

z=1. 7495

Photometric vs Spectroscopic Redshift VLT(ESO)

Photometric Redshift Bz. Ks EROs

Photometric Redshift DRGs

Internal reddening Bz. K ERO • B-z (the slope of UV spectrum) color E(B-V) of SFGs. • Bz. Ks are dusty galaxies Kong, Charlot, Brinchman, Fall (2004) • ERO: OGs & DGs have different internal reddening.

Stellar Mass Bz. Ks Stellar mass EROs : based on multi-color photometry EROs and Bz. Ks are similar (on average) 30% Bz. Ks & EROs : M>1. 0 E 11 M @ Deep 3 a-F Klim=20. 2 mag 55% Bz. Ks & EROs : M>1. 0 E 11 M @ Daddi-F Klim=18. 8 mag

Star Formation Rate UV Flux: 1500 A<λ<2800 A NIR spectra (Subaru) • Dad 1901 SFR(Ha)=60 M /yr SFR(UV)=70 M /yr • Dad 2326 SFR(Ha)=250 M /yr SFR(UV)=180 M /yr • Bz. Ks have high SFRs • EROs : OGs/DGs diff.

burst age reddening stellar mass SFR

Culling K-band Luminous, Massive Star Forming Galaxies at z>2

Sky positions of Bz. Ks & EROs Bz. Ks EROs Angular two-point correlation function: w(q)= (DD-2 DR+RR)/RR＝Aq-d Landy & Szalay (1993) (d=0. 8)

Clustering Properties Field Galaxies EROs Bz. Ks

A New Population of near-IR bright, z～ 2 Galaxies K>20 HST/ACS F 435 W, F 850 LP & K-band (VLT+ISAAC) A sample of 9 galaxies at 1. 7<z<2. 23 with bright K-band magnitudes 18. 7<K<20 has recently been discovered (Daddi et al. 2003, astro-ph/0308456).

• Bz. Ks – – Summary High internal reddening : E(B-V)～ 0. 5 strong star formation : SFR～ 200 M /yr Massive galaxies : >30％ (K=20) M>1. 0 E 11 M Strong 2 -D clustering • EROs (R-K>5) : DGs & OGs – – OGs: passive galaxies DGs: some of them are Bz. Ks OGs have low SFRs Strong clustering and massive • LBGs E(B-V)≤ 0. 3, SFR< 70 M /yr, clustering

Summary Bz. K selection is a quite powerful way to separate star forming galaxies at 1. 4<z<2. 5. Bz. Ks are different from LBGs (low extinction, low SFR). Some Bz. Ks are dusty EROs (high extinction, low SFR), but most of Bz. Ks are not EROs. K-band luminous, massive, high-SFRs galaxies at z>2 are likely to be possible precursors of z～ 1 passively evolving EROs and z=0 elliptical galaxies. Submm galaxies are sub-populations of Bz. Ks with extremely high SFRs and metallicities.

Conclusions We have discovered a new population of reddened, vigorous star-forming massive galaxies at z>2. Their masses, likely extremely high star formation rates, HST/ACS morphologies, clustering properties, all suggest that they may be the long-sought-for progenitors of nearby massive ellipticals, close to their epoch of formation. What Next? 1) Confirming the High SFRs, High metallicity 2) Contribution to the z>2 SFR Density 3) Understand the link between Bz. K and Submm Gals 4) CO follow-up 5) Co-evolution of Bz. K and Massive BHs ……… 6) COSMOS, NEP. SXDS, etc to see cosmic variance