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

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.

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

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  1. 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)

  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). Near IR wide field imaging is crucial. Fully assembled massive galaxies with Ms>1011Mo at z>2 are extremely rare. Mass Function Evolution (Baugh et al. 2002)

  3. Previous NIR Image Surveys 1. Hubble Deep Field North & South 2x5.3 arcmin2 2. K20 (NTT) 52 arcmin2 3. Subaru Deep Field (Ks=22.6) 4 arcmin2 4. Subaru XMM Deep Field (Ks=22.1) 114 arcmin2 5. Goods (HDF-N & CDF-S) 160 arcmin2 6. Hubble Ultra Deep Field (NICMOS) 5.8 arcmin2 7. EIS3a-F (Subaru/VLT, Ks=20.8) 900 arcmin2 8. Daddi-F (Subaru/VLT, Ks=19.0) 900 arcmin2

  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

  6. K-band Galaxy Number Counts

  7. K-selected High-z Galaxies • 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 780 EROs in Deep3a-F 380 EROs in Daddi-F 240 DRGs in Deep3a-F 2. Distant Red Galaxies (DRGs) Frank et al. (2003) J-K>2.3, z>2

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

  9. BK20=BEISzK20=zEIS-0.16

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

  11. B R I z’ J K

  12. BzK(ERO) BzK BzK BzK ERO ERO ERO ERO

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

  14. z=1.7495

  15. Ｌｙα z=2.3894 ＣＩＶ

  16. Ｌｙα z=2.8453 ＣＩＶ

  17. Photometric vs Spectroscopic Redshift VLT(ESO)

  18. Photometric Redshift BzKs EROs

  19. Photometric Redshift DRGs

  20. Internal reddening BzK ERO • 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)

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

  22. Star Formation Rate UV Flux: 1500A<λ<2800A 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.

  23. burst age reddening stellar mass SFR

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

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

  26. Clustering Properties Field Galaxies Field Galaxies EROs EROs BzKs BzKs

  27. A New Population of near-IRbright, 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).

  28. Summary • BzKs • High internal reddening : E(B-V)～0.5 • strong star formation : SFR～200 M/yr • Massive galaxies : >30％ (K=20) M>1.0E11M • 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

  29. 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.

  30. 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? • Confirming the High SFRs, High metallicity • Contribution to the z>2 SFR Density • Understand the link between BzK and Submm Gals • CO follow-up • Co-evolution of BzK and Massive BHs ……… • COSMOS, NEP. SXDS, etc to see cosmic variance

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