Clustering Properties of Clustering Properties of Star Forming - PowerPoint PPT Presentation

Clustering Properties of Clustering Properties of Star Forming Galaxies at z ~ 2 Star Forming Galaxies at z ~ 2 BzK 銀河のクラスタリングから探る BzK 銀河のクラスタリングから探る z ～ 2 の星形成銀河の形成と進化 z ～ 2 の星形成銀河の形成と進化 Masao Hayashi Masao Hayashi (Univ. of Tokyo) (Univ. of Tokyo) collaborators collaborators K. Shimasaku K. Shimasaku 、 、 K. K. Motohara Motohara 、 、 M. Yoshida M. Yoshida 、 、 S. Okamura (Univ. of Tokyo) 、 N. Kashikawa Kashikawa （ NAOJ ） S. Okamura (Univ. of Tokyo) 、 N. （ NAOJ ） 2007/1/30 2007/1/30

The universe at z~2 The universe at z~2 Galaxy formation and evolution based on the CDM model Galaxy formation and evolution based on the CDM model � � � strong dependence on mass of dark strong dependence on mass of dark- -halo (DH) (Mo & White 2002) halo (DH) (Mo & White 2002) � The era of z~ z~2 2 The era of � � Drastic changes occurred in the galaxy population at z~2 Drastic changes occurred in the galaxy population at z~2 � The cosmic SFR and the number density of QSO have a peak at z~2 The cosmic SFR and the number density of QSO have a peak at z~2 � (e.g., Dickinson et al. 2003; Richards et al. 2006) (e.g., Dickinson et al. 2003; Richards et al. 2006) � A significant evolution of the Hubble sequence occurred at z=1 A significant evolution of the Hubble sequence occurred at z=1- -2 2 � (Kajisawa Kajisawa & Yamada 2001; & Yamada 2001; Conselice Conselice et al. 2005) et al. 2005) ( Galaxies at z~2 （ redshift desert desert ） Galaxies at z~2 （ redshift ） � � � BzK BzK color selection color selection � ⇒ BzK BzK galaxies galaxies ( (Daddi Daddi et al. 2004) et al. 2004) ⇒ � The only selection method of galaxies at z~2, The only selection method of galaxies at z~2, � irrespective of the amount of dust extinction irrespective of the amount of dust extinction The Mass of dark- The Mass of dark -haloes hosting galaxies at z~2 is haloes hosting galaxies at z~2 is inferred from clustering strength. inferred from clustering strength.

BzK galaxies @ 1.4<z<2.5 galaxies @ 1.4<z<2.5 BzK Star-forming BzKs B z ’ K B z K ’ Passive BzKs Bruzual & Bruzual & Charlot Charlot (2003) (2003) B z ’ K B z K ’ E(B-V) Daddi et al. (2004)

Optical and NIR data in the SDF SDF Optical and NIR data in the � B, z B, z ’ , K ’ , K � Suprime- -Cam Cam � optical : Subaru/ optical : Subaru/Suprime Suprime- -Cam Cam Suprime � NIR : UKIRT/WFCAM NIR : UKIRT/WFCAM � limiting limiting mag.(AB mag.(AB, 2 , 2 ” ” aperture) aperture) NW NW � � B : 28.8 ( B : 28.8 ( ２ ) σ ) ２σ � � z z ’ ’ : 27.0 ( : 27.0 ( ２ ) σ ) ２σ � These areas are used for These areas are used for � K : 23.5 (5 K : 23.5 (5 σ ) σ ) clustering analysis clustering analysis � WFCAM WFCAM � seeing : 1.14 seeing : 1.14 ” ” � SW SW � areas used for clustering areas used for clustering � analysis analysis � NW area : ~100 arcmin NW area : ~100 arcmin 2 2 � � SW area : ~80 arcmin SW area : ~80 arcmin 2 2 �

BzK galaxies in the SDF galaxies in the SDF BzK star- star -forming forming passive passive K AB 23.2 BzK BzK ’ s samples samples K ≦ 23.2 ’ s AB ≦ z ’ -K SW NW total SW NW total Star Star- -forming forming 419 419 673 673 1092 1092 Passive 20 36 56 Passive 20 36 56 (The limiting magitude (The limiting magitude of the of the samples is total magnitude.) samples is total magnitude.) K AB <23.5 B-z ’

Celestial distribution of BzKs BzKs Celestial distribution of Star-forming BzKs passive BzKs SW NW Star-forming BzKs passive BzKs K AB K ≦ 23.2 samples 23.2 samples AB ≦ SW NW total SW NW total Star- -forming forming 419 673 1092 Star 419 673 1092 Passive Passive 20 20 36 36 56 56

Angular correlation function of Angular correlation function of star- -forming forming BzKs BzKs star star-forming BzK K AB ≦ 23.2 A=0.58 ± 0.13 A=0.58 ± 0.13 Measurements from the two Measurements from the two subregions are averaged. are averaged. subregions ACF is assumed to be power law, W( W( θ )=A θ ACF is assumed to be power law, θ )=A θ - -0.8 0.8 � � Errors are estimated using bootstrap resample method Errors are estimated using bootstrap resample method � � (Error bars are 1 σ ) (Error bars are 1 σ ) The sample of passive BzKs BzKs is too small to obtain a reliable result is too small to obtain a reliable result The sample of passive � �

Translation of ACF into SCF Translation of ACF into SCF � ACF ACF ⇒ ⇒ Spatial Correlation Function (SCF) Spatial Correlation Function (SCF) � (r)=(r/r )=(r/r 0 ) - ξ (r 0 ) -1.8 1.8 � ξ ACF � r 0 : correlation length r 0 : correlation length K AB ≦ 23.2 � If If redshift redshift distribution is known, distribution is known, � r 0 is culculated culculated from amplitude of the ACF from amplitude of the ACF r 0 is using Limber ’ using Limber ’ s equation. s equation. A=0.58 ± 0.13 N(z) of star ) of star- -forming forming BzKs BzKs is assumed to is assumed to N(z � � be a Gaussian with z z c =1.9 1.9 、 =0.35 ± 0.1. be a Gaussian with c = σ =0.35 ± 0.1. 、σ N(z) Histogram of N(z N(z) shows that of ) shows that of Histogram of � � star- -forming forming BzKs BzKs with K<22. with K<22. star spectroscopic redshifts redshifts are contained. are contained. ） （ spectroscopic （ ） (Daddi Daddi et al. 2004) et al. 2004) ( correlation length (r 0 ) ⇒ ⇒ DH DH mass mass correlation length (r 0 )

correlation length （ r 0 ） and DH mass of and DH mass of correlation length （ r 0 ） star- -forming forming BzKs BzKs star The r 0 of bright BzKs BzKs is calculated from the ACF given in Kong et al. (2006) (K06). is calculated from the ACF given in Kong et al. (2006) (K06). The r 0 of bright Brighter star- -forming forming BzKs BzKs are hosted by more massive dark haloes. are hosted by more massive dark haloes. Brighter star

The stellar mass and DH mass The stellar mass and DH mass of star- -forming forming BzKs BzKs of star 10 14 10 13 DH mass DH mass s s a m 10 12 H D ＝ s s a m 10 11 r a l l e t S 10 10 10 12 10 10 10 11 Stellar mass Stellar mass The mass of dark- The mass of dark -haloes largely increases with the stellar mass. haloes largely increases with the stellar mass.

Comparison of correlation length Comparison of correlation length with other galaxy populations with other galaxy populations faint (K AB <23.2) star- -forming forming BzK BzK faint (K AB <23.2) star � � BX/BM @ z~2 BX/BM @ z~2 � � LBG @ z~3 LBG @ z~3 � � ⇒ M M DH DH ~10 ~10 11 11 Msun Msun ⇒ bright (K AB <21.9) star- -forming forming BzK BzK bright (K AB <21.9) star � � ERO @ z~1- -2 2 ERO @ z~1 � � DRG @ z~2 DRG @ z~2- -3 3 � � cluster @ z~0 cluster @ z~0 � � ⇒ M M DH ~10 13 13- -14 14 Msun Msun DH ~10 ⇒ Faint star Faint star- -forming forming BzKs BzKs and optically selected star and optically selected star- -forming forming galaxies at z~2 are similar populations. galaxies at z~2 are similar populations.

Present- -day descendants day descendants Present of star- -forming forming BzKs BzKs of star extended Press extended Press- -Schechter Schechter formalism formalism � � This formalism predicts the mass This formalism predicts the mass growth of dark- -haloes. haloes. growth of dark � K K AB <20.4 AB <20.4 � M DH (z=2) = 1.6 =2) = 1.6 × 10 14 Msun ⇒ M DH (z × 10 14 Msun ⇒ 14 Msun M DH M DH (z~0) = 4.3 (z~0) = 4.3- -9.3 9.3 × × 10 10 14 Msun � K K AB AB <23.2 <23.2 � 11 Msun M DH (z=2) = 2.8 =2) = 2.8 × 10 11 Msun ⇒ M DH (z × 10 ⇒ 11 Msun M DH M DH (z~0) = 3.7 (z~0) = 3.7- -10.0 10.0 × × 10 10 11 Msun Star- -forming forming BzKs BzKs evolve into galaxies over a wide range of mass, evolve into galaxies over a wide range of mass, Star depending on their apparent K brightness. depending on their apparent K brightness.