1. Culling K-band Luminous, Massive Star Forming Galaxies at z>2 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) N. ARIMOTO (NAOJ)

2. 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). Mass Function Evolution (Baugh et al. 2002) Fully assembled massive galaxies with Ms>10 11 Mo at z>2 are extremely rare. Near IR wide field imaging is crucial.

3. Previous NIR Image Surveys 1. Hubble Deep Field North & South 2x5.3 arcmin 2 2. K20 (NTT) 52 arcmin 2 3. Subaru Deep Field (Ks=22.6) 4 arcmin 2 4. Subaru XMM Deep Field (Ks=22.1) 114 arcmin 2 5. Goods (HDF-N & CDF-S) 160 arcmin 2 6. Hubble Ultra Deep Field (NICMOS) 5.8 arcmin 2 7. EIS3a-F (Subaru/VLT, Ks=20.8) 900 arcmin 2 8. Daddi-F (Subaru/VLT, Ks=19.0) 900 arcmin 2

4. Subaru/Sup-Cam Observation ESO Imaging Survey (EIS Deep 3a) Field RA=11:24:50, DEC=-21:42:00 (J2000.0) 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

5. Subaru/Sup-Cam Observation Daddi Field RA=14:49:29, DEC=09:00:00 (J2000.0) 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

8. K-band Galaxy Number Counts

9. K-selected High-z Galaxies 780 EROs in Deep3a-F 380 EROs in Daddi-F 240 DRGs in Deep3a-F 1.Extremely Red Objects (EROs) McCarthey 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

10. New Galaxy Population (BzKs) Daddi et al. (2005): BzK=(z-K)AB-(B-z)AB>-0.2

11. B K20 =B EIS z K20 =z EIS -0.16

12. High-z galaxies in our fields Star-forming galaxies at z>1.4 (BzKs) Old galaxies at z>1.4: PEGs stars BzKs 425 BzK in Deep 3a 145 BzK in Daddi-F

13. B R I z ’ J K

14. BzK(ERO) BzK BzK BzK ERO ERO

15. Z=1.5564 VLT Observation of ～ 300 BzK galaxies ＣＩＶ

16. z=1.7495

17. z=2.3894 ＣＩＶ Ｌｙ α

18. z=2.8453 Ｌｙ α ＣＩＶ

19. Photometric vs Spectroscopic Redshift VLT(ESO )

20. Photometric Redshift BzKs EROs

21. Photometric Redshift DRGs

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

23. Stellar Mass Stellar mass : based on multi-color photometry EROs and BzKs are similar (on average) 30% BzKs & EROs : M>1.0E11M  @ Deep3a-F K lim =20.2 mag 55% BzKs & EROs : M>1.0E11M  @ Daddi-F K lim =18.8 mag BzKsEROs

24. Star Formation Rate NIR spectra (Subaru) Dad1901 SFR(Ha)=60 M  /yr SFR(UV)=70 M  /yr Dad2326 SFR(Ha)=250 M  /yr SFR(UV)=180M  /yr BzKs have high SFRs EROs : OGs/DGs diff. UV Flux: 1500A<λ<2800A

25. burst agereddening stellar massSFR

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

27. Sky positions of BzKs & EROs Angular two-point correlation function: Landy & Szalay (1993) w(q)= (DD-2DR+RR)/RR ＝ Aq -d ( d=0.8) BzKsEROs

28. Clustering Properties Field Galaxies EROs BzKs

29. A New Population of near-IR bright, z ～ 2 Galaxies K>20 HST/ACS F435W, F850LP & 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).

30. Summary BzKs –High internal reddening : E(B-V) ～ 0.5 –strong star formation : SFR ～ 200 M  /yr –Massive galaxies : >30 ％ (K=20) M>1.0E 11 M  –Strong 2-D clustering EROs (R-K>5) : DGs & OGs –OGs: passive galaxies –DGs: some of them are BzKs –OGs have low SFRs –Strong clustering and massive LBGs E(B-V)≤0.3, SFR< 70 M  /yr, clustering

31. Summary BzK selection is a quite powerful way to separate star forming galaxies at 1.4<z<2.5. BzKs are different from LBGs (low extinction, low SFR). Some BzKs are dusty EROs (high extinction, low SFR), but most of BzKs 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 BzKs with extremely high SFRs and metallicities.

32. 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 BzK and Submm Gals 4)CO follow-up 5)Co-evolution of BzK and Massive BHs ……… 6)COSMOS, NEP. SXDS, etc to see cosmic variance