Clustering of BzK-selected galaxies in the COSMOS field Xu KONG collaborators ： A. Renzini, E. Daddi, N. Arimoto, A. Cimatti ， COSMOS team Venice

1. Introduction NIR/Spect. Surveys (good points: k-corrections, dust extinction, instantaneous SFH, stellar mass …) –HDF (2x5.3 arcmin 2 ) UDF (5.76 arcmin 2 ) SDF ( 4.0arcmin 2 ) –K20 (52.0 arcmin 2 ) SXDF (114.0 arcmin 2 ) GOODS (320.0arcmin 2 ) –GDDS GEMS MUNICS –VVDS DEEP2 GMASS We are working on … –EIS-Deep3a: 900 arcmin 2 NIR survey (Deep3a-F,Daddi-F) Prof. Arimoto, Renzini, Daddi talks, Masato poster Kong et al. 2006, ApJ, 638, 72 –COSMOS : 2 deg 2 NIR survey (BzKs/EROs)

2. COSMOS Fields : RA (J2000) = 10:00:28.6 DEC (J2000) = +02:12:21.0 Catalog : 2 January 2006 – P. Capak, B. Mobasher, N.Z. Scoville (PI) – released_ _photz.cat i_auto < 25 mag (AB system) : objects B_mask=0 : objects Sampling: objects Area: RA ( ); DEC ( ) K_tot<19.2; err_K<0.25; B_mask=0

RA: DEC: – 2.910

3. Photometric Catalog NIR : Ks band gal. BzKs & EROs K-band number counts

4.1 Selection of BzKs Daddi et al. (2004, ApJ, 617,746) K20 Survey ： VLT Large Program –50. arcmin 2 –~ 500 spectra –SFGs BzK> -0.2 BzK=(z-K) AB -(B-z) AB BzK >-0.2 : sBzKs BzK 2.5 : pBzKs sBzKspBzKs

4.1 Selection of BzKs BzK=(z-K) AB -(B-z) AB BzK >-0.2 : sBzKs BzK 2.5 : pBzKs sBzKs pBzKs CWW templatesBC03 templates

4.2 Selection of EROs R-K>5 (Vega) R-K>3.35 (AB) ip-K>2.45 (AB)

4.3 High-z Galaxies in COSMOS sBzKs: 1287 star-forming z>1.4 pBzKs:195 old z>1.4 EROs: 5090 z~1 galaxies (OGs/DGs) Stars in COSMOS Stars in K20 low~z galaxies

4.3 High-z Galaxies in COSMOS sBzKs: 1287 star-forming z>1.4 pBzKs:195 old z>1.4 EROs: 5090 z~1 galaxies (OGs/DGs) Stars in COSMOS Stars in K20 low~z galaxies

4.4 number counts of high-z n.c. of sBzKs:same slope; steep n.c. of EROs:break Field galaxies,sBzKs, EROs : similar pBzKs: different why ?? B-band shallow?

5.1 Clustering of galaxies EROs: 0.77/arcmin^2 sBzKs: 0.195/arcmin^2

5.2 Clustering of galaxies Clustering of field galaxies Amplitudes ~ published values Clustering of EROs A ~ published values K fainter, A decrease Clustering of BzKs A is large K fainter, A decrease Landy & Szalay (1993)  (DD-2DR+RR)/RR ＝ A    Angular 2-point correlation function

BzKs are strong clustering! 5.3 Clustering of galaxies Clustering of field galaxies Amplitudes ~ published values Clustering of EROs A ~ published values K fainter, A decrease Clustering of BzKs A is large K fainter, A decrease

6.1 Photometric Redshift BzK selection is a quite powerful way to separate galaxies at 1.4<z<2.5 EROs sBzKs

6.1 Photometric Redshift

6.2 E(B-V) SFR Mass sBzKs : z~1.8 (Daddi. et al.) K <19.2 –B-z  UV Slope  E(B-V) sBzKs are dusty galaxies, E(B-V) ~ 0.42 –B band  1600A  SFR sBzKs have high SFRs, SFR ~ 430 M  /yr –SED fitting  M * Most BzKs are massive galaxies, M ~ 1.5E11 M 

6.3 SFRD/MD at redshift~2 For K<19.2 mag. – SFRD at z~2 : M  /yr – Mass densities : logρ*=7.1 M  Mpc-3

sBzKs EROs 6.3 Morphology sBzKs: irregular EROs : E/S0

Conclusion BzKs (K<19.2) –High redshift 1.4<z<2.5 –high internal reddening E(B-V)~0.45 –strong star formation SFR~400 M  /yr –Massive galaxies. >80 ％ M>1.0E11M  –Strong 2-D clustering A(BzKs)≥A(EROs) BzKs are likely to be possible precursors of z ～ 1 EROs and z=0 elliptical galaxies. We will do on COSMOS … –High-z cluster candidates –Morphology of BzKs & EROs –Hubble sequence at z~2 THANKs!

B>27.5