Galaxy in Real Life and Simulations (Leiden, 17/09/2008)

When and Where Did Early-Type Galaxies Form?

Taddy Kodama (NAOJ), PISCES team [M.Tanaka (ESO), Y.

Koyama (Univ of Tokyo)], and HzRG team [De Breuck, Doherty, Seymour, Joel, Kurk, Venemans, Stern, Miley, Kajisawa, I.Tanaka, M.Tanaka, et al.]

Outline

Environmental Effects in Cluster Outskirts

(Optical/Space-IR, PISCES, 0.4<z<1.4)

“dusty starbursts and truncation in groups” Massive Galaxy Formation in Proto-Clusters

　　　　 　 (NIR, HzRG, 2<z<5)

“emergence of red sequence at z~2”

“When and where did early-type galaxies form?”

z = 30 z = 5

z = 2z = 3

z = 0z = 1

Origin of Environmental DependenceN-body simulation of a massive cluster

　　　　　　 Nature?

Ellipticals form early in the highest density peaks while Spirals form later in lower density regions.

　　　　　　 Nurture?

Transformation of Spirals to E/S0s as they assemble to denser regions.

MOIRCS (NIR)

4’×7’

34’×27’Suprime-Cam (Opt)

M=6×1014 M◎ 20×20Mpc2 (co-moving)

★Optical Survey with S-Cam (0.4<z<1.4):

Kodama et al., Tanaka et al., Koyama et al., PISCES team

★NIR survey with MOIRCS (2<z<5):Kodama et al., Kajisawa et al., HzRG team

(Yahagi et al. 2005)

ACS(3.5’)

XMM1.14

PPanoramic anoramic IImaging and maging and SSpectroscopy ofpectroscopy of 　　 CCluster luster

EEvolution with volution with SSubaruubaru

XMMU2235.3-2557 22 35 20.6 -25 57 42.0 1.393 3.0 VRi’z’XMMXCSJ2215.9-1738 22 15 58.5 -17 38 02.5 1.45 4.4 VRi’z’

z~1.4XMMXMM

17 X-ray detected clusters at 0.4 < z < 1.45 (~70% completed)

Kodama et al. (2005)

Name redshift NIR Spitzer Lya spectra others

PKS 1138-262 2.16 JHKs 3.6--8.0 16 NIR/Opt Ha, VLA, Chandra, SCUBA4C 23.56 2.48 JHKs 3.6--8.0 NIR HaUSS 1558-003 2.53 JHKs 3.6--8.0 USS 0943-242 2.92 JHKs 3.6--24.0 29 OptMRC 0316-257 3.13 JHKs 3.6--8.0 32 NIRTNJ 1338-1942 4.11 JHKs 3.6--8.0 37 Suprime-Cam, VLA, MAMBOTNJ 0924-2201 5.19 JHKs 3.6--24.0 6 Suprime-Cam/ACS (LBGs)

HHighigh R Redshiftedshift R Radioadio G Galaxiesalaxies ((HzRGHzRG) with Subaru, VLT, and ) with Subaru, VLT, and

SpitzerSpitzer7 confirmed proto-clusters at 2 < z < 5.2 associated to radio galaxies

Kodama et al. (2007), De Breuck et al. (Spitzer HzRGs)

Overdense in Lyman-α emitters by a factor 3—5.

RXJ0152-13 at z=0.83VRizK photometry + 200 spec. objects

ACS/HST

z=0.83 (7Gyr ago) z=0.55 (5.4Gyr ago)

Spatial distribution of phot-z members (Δz = － 0.05~+0.03)

Kodama, et al. (2005)

z = 1

simulation

Panoramic Views of Cluster Assembly

RXJ 0152.7-1357 (VRIz’) CL 0016+16 (BVRi’z’)

0.835

0.8420.837

0.835

0.844

0.7820.745

0.844

Tanaka, TK, et al. (2005b; 2007)

30 Mpc (co-moving)

RXJ 0152.7-1357 (z=0.83)

0.547

0.548

0.546

0.550

0.549

0.542

0.5500.547

FOCAS

Spectroscopic Confirmation of LSS

Physical association of most of the structures have been confirmed!

~200-300 redshifts per cluster

CL 0016+16 (z=0.55)

CL0016 cluster (z=0.55)

(Tanaka, et al., in prep.)

HSC / WFMOSMillenium Simulation(Springel et al. 2005)

A Huge Cosmic Web at z=0.5 over 50 Mpc (80’x80’ by 7 S-Cam ptgs.)

S-Cam

Traced by red-sequence galaxies in V-I colours

銀河の色は中間的な環境で急激に変化する

hig

h

med

low

（

赤い銀河の割合

）

high ～ cluster core

med ～ group / filament

low ～ field

Sharp Colour Transition in Groups/Filaments

RXJ1716 Cluster （ z=0.81 ）

Koyama, TK, et al. (2008), accepted by MNRAS, arXiv:0809.2795

AKARI “Deep” and “Wide” MIR Imaging of a NEP Cluster RXJ1716 (z=0.81)

N3 （ 3um ） ＝ 105 min

S7 （ 7um ） ＝ 115 min

L15 （ 15um ） ＝ 120 min

Spitzer

AKARI

PAH (6-7μm) at z=0.8

Subaru

SFR > 20 Msun/yr (LIRG, ULIRG)

Part of the data comes from CLEVL (mid-z) (PI: H.M.Lee)

IR satellite, D=69cm, 1.7<λ<180μm

Spatial Distribution of the 15μm sources

Koyama, TK, et al. (2008), arXiv:0809.2795

A void of 15um sources at the center!

15 μm galaxies are preferentially found in medium density regions.

f(15μm) > 67 μJy

Dusty star-bursting galaxies in groups/filaments at z~0.8 (Subaru + AKARI)

z’ ～　 Stellar Mass

L15 ～　 Star Formation Rate

z’ － L15

＝－ 2.5 log [ f (z’) / f (15) ]

　 ～　 SFR / M(star)

large z’ － L15

　⇔　 large SF efficiency

“specific star formation rate”

High SSFR

Interacting Galaxies in the 15μm sources

Koyama, , TK, et al. (2008), MNRAS accepted, arXiv:0809.2795

16”

= 1

30kp

c

Subaru(optical)

AKARI(NIR)

Summary for PISCES (0.4<z<1.4)

Assembly of Clusters of Galaxies Large scale structures (>10Mpc) are commonly seen as

direct evidence for hierarchical growth of clusters. Origin of Environmental Dependence Enhancement and subsequent truncation of star forming

activity is seen in medium-density (group) environment, probably due to galaxy-galaxy interaction.

Down-Sizing as a Function of Environment Time scale of galaxy formation and evolution is dependent

on mass of galaxies and environment. Massive, High-density Less-massive, Lower-density

Stanford et al. (2006)Lidman et al. (2008)

Hawk-I data !

XMMJ2235 (z=1.39) XMMJ2215 (z=1.45)

When does the red-sequence eventually break down ？The most distant X-ray clusters to date

z(star formation)>2, z(assembly)>1.5

Well-visible red sequence consistent with passive evolution formed at z>3. They are very massive (>1011M ◎) !

● DRG(J-K>2.3)

RG

25 arcmin^2 25 arcmin^2

PKS1138 (z=2.16) USS1558 (z=2.53)

Red sequence of proto-clusters at z~2—2.5

● r-JHK ● b-JHK

Clear excess of red galaxies consistent with passive evolution formed at z>4,but few massive ones (> 1011M ◎) ! not assembled yet !?

RG

USS0943 (z=2.92)

Red sequence of proto-clusters at z~3

MRC0316 (z=3.13)

● r-JHK ● b-JHKUSS0943 (z=2.923)

simple fading

more SF orwet mergers

dry mergers

Where are the progenitors of massive galaxies at z~3?

SFR of 100 Msun/yr x 1 Gyr = 1011 Msun

Simple fading alone doesn’t work because there are no massive blue counterparts!

Spectroscopic follow-up in progress…

Subaru/MOIRCS (NIR, ~30 slits over 7’×4’, R=1300, 5 hrs)

Subaru/FOCAS (optical, ~30 slits over 6’φ, R=1000, 5 hrs)

VLT/FORS2 (optical, ~30 slits over 7’×7’, R=1000, 5 hrs)

3 Hα emitters (members) are detected around 4C23.56 (z=2.483)2 Hα emitters (members) are detected around PKS1138 (z=2.156)

6 redshifts (Lyα+) are measured for USS0943 (z=2.923),of which 2 are members (LAE, b-JHK), while the others are stillwithin 2.4<z<3.1, consistent with our b-JHK selection.

11 redshifts (Lya+) are measured for USS0943 (z=2.923),of which 2 are members, while 4 out of 9 others are stillwithin 2.4<z<3.1, consistent with our JHK selection.

Extremely unlucky with weather so far! (7 out of 9 Subaru nights were clouded out!)Nevertheless…

We don’t see many strong emissions... Need to search for continuum break and/or absorption lines.

K-band spectra with Subaru/MOIRCS (4.7 hours, R=1300, 4’x7’)

4C23.56 (z=2.483)

4 Hα emitters including the RG.

Summary for Proto-Clusters (HzRG)

Multi-wavelength approach is crucial to disentangle which of the two processes, star formation or mass assembly, is dominant in formation of massive galaxies. Environmental dependence? Earlier epoch?

Assembly of Proto-Clusters

Clustering of many red galaxies (overdensity by a factor of 2-4) around high-z radio-loud galaxies shows the early stage of cluster-scale assembly.

Site of Massive Galaxies Formation

　 Massive galaxies (>1011M◎) are formed rapidly between z=3 and 2 (2~3 Gyr after the Big-bang).

Summary for the Distant Cluster Studies with Subaru

Groups in the outskirts of clusters are the key hierarchy for truncation/transformation of galaxies.

The redshift interval of 2<z<3 is the key era for the formation of massive galaxies in high-density regions.

Formation of S0s (and some Es)

Formation of Es (and some S0s)

Questions for Discussion• How can we compare clusters at different redshifts?

We are likely probing most biased regions (known overdense regions) at any epoch, therefore we can naively expect an evolutionary link between them? But this does not tell us a general formation picture of clusters seen today which can have various assembly histories.

• How can we normalize luminosity (stellar-mass) functions?

We don’t know mass of the systems: velocity dispersion may not work. “overdensity” “mass” using SAMs?

• Do we see any environmental dependence at high-z?

We expect to see a reversal of star formation-density relation at high-z due to galaxy formation bias?

• How much star formation is hidden by dust on the red sequence?