z~1と0の銀河団における早期型銀河の等面輝度形状について(Isophote Shapes of Early-Type Galaxies
in Massive Clusters at z~1 and 0,

submitted to ApJ by K. Mitsuda, M. Doi, T. Morokuma, N. Suzuki, N.
Yasuda, S. Perlmutter, G. Aldering, J. Meyers)

Kazuma Mitsuda
University of Tokyo2016年6月1日水曜日

1Outline● Introduction
・ Early- and late-type galaxies● Observed properties of early-type galaxies (ETGs)
・ Dynamical properties of ETGs・ Stellar population of ETGs
・ Isophote Shapes of ETGs
● Our study
・ Isophote shapes of z~1 ETGs
・ Summary & future work

2016年6月1日水曜日

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0 Early- and late-type galaxies
Early-type Galaxies (ETGs)
EllipticalS0Late-type Galaxies
SabScdBulgeDiskRandom motionRotation

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1.1 Dynamics of ETGs : fast/slow rotators● IFS Survey of Nearby Galaxies (ATLAS3D, CALIFA, SAMI, MANGA, etc...)☀ Integral ﬁeld spectroscopic (IFS)

survey of nearby ETGs

Photometry

Velocity Field

Velocity
Dispersion Field☀ ETG subclass: fast/slow rotators(Emsellem+11: ATLAS3D)☀ ETGs become dispersion dominatedwith increasing masstroowSle

σnttans

Dispersion dominated= slow rotators

Angular momentum

CoRotation dominated= fast rotators

Velocity Field

Re[kpc](half-light radius)

Velocity Field

Fast rot
MJAM(dynamical mass)

Capperalli+13

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1.2 Stellar population of ETGs on the Mass-Size Plane
Star formation
time-scale

H2 fraction

nstantσeMetallicity

CoRe(half-light radius)

AgeMJAM(dynamical mass)

McDermid+15

Cappellari+13☀ Age, metallicity, star formation time-scales, and H2 fractionconstant along constant velocity dispersion
Stellar populations become older & more metal richwith increasing velocity dispersion (increasing bulge fraction)

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1.3 Two Phase Scenario for ETG Formation & Evolution☀ Phase I (z~2-3?)

Bulge formation indissipative processes
Fast rotators?

obs.) Clumpy disks at z>2

Re[kpc](half-light radius)

MJAM(dynamical mass)

Dynamics

MJAM(dynamical mass)

2016年6月1日水曜日

Re(half-light radius)Re(half-light radius)

Stellar Population☀ Phase II (z<2?)

MJAM(dynamical mass)Size growth and dynamical evolution
by dissipationless processes
Slow rotators?

Cappellari+13obs.) Rapid size growth of ETGs in z<2How can we investigate dynamical evolution of ETGs at high-z?
(observationally too expensive)

Isophote Shapes can be a proxy for dynamics
62.1 Isophote Shapes of Early-Type Galaxies : Boxy/DiskyETGs
Boxy EDisky ES0Sab

Scd

Dispersion

Rotation
Kormendy&Bender 96

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2.2 Boxy/Disky Classiﬁcation"r!

10Ellipse

5-5-10IsophoteDisky0Boxy●Ellipse : x = a cos("), y = b sin(")(a: semi-major axis, b: semi-minor axis)●Fourier Expansion of !r50-5!r = ! an cos(n") + ! bn sin(n")

a4 < 0 : boxy
a4 > 0 : diskye.g., Bender&Möllenhoﬀ 87

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8sp.)- Supported by random motion#(di... dissipationlessor ʼdryʼ processes

Disky ETGs (a4 > 0)
● Rotation dominated- Rotation is important for the system... dissipativeor ʼwetʼ processes

V(rot.)
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Kormendy&Bender+96

log (V / #)*● Dispersion dominatedDispersion

Boxy ETGs (a4 < 0)Rotation

2.3 Boxy/Disky (a4) as a Proxy for Slow/Fast Rotators

Boxy a4 / a [%]Disky92.4 Example of the Redshift Evolution Prediction● A theoretical prediction of the disky/boxy fraction(Khochfar+11)- Cosmological simulation (semi-analytic)

from Khochfar+11

6※ Low-z: gas-poor mergers? (phase2)
boxy ETG formed later● Few high-z observations- 18 ETGs at 0.6 < z < 1.1 (Pasquali+06)- Disky/boxy fraction stays the same

Contradicts to the Khochfar+11ʼs simulation- Not conclusive due to small sample" f (disky/boxy)※ High-z: gas-rich processes (phase1)
disky ETG formed earlierf(disky/boxy)- Disky fraction increases at higher-z

M0154M＊

⦿01>

3211 M⦿

01>
M＊

100

0.2 0.4 0.6 0.8

1redshift(z)redshift ( z )2016年6月1日水曜日

10Outline● Introduction
・ Early- and late-type galaxies● Observed properties of early-type galaxies (ETGs)
・ Dynamical properties of ETGs・ Stellar population of ETGs
・ Isophote Shapes of ETGs
● Our study
・ Isophote shapes of z~1 ETGs
・ Summary & future work

2016年6月1日水曜日

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3.1 Early-Type Galaxy Samples (Overview)● High-z (z~1)☀ Hubble Space Telescope (HST) multi epoch imaging (i, z) (Suzuki+12)※ HST Cluster Supernova Survey (Dawson+09)

PSF FWHM : 0.1 arcsec
Integration time : > 10ks (z)ETG@z~1☀ 175 ETGs with log(M＊/M⦿)>10.3
Members of z~1 galaxy clusters
With spectroscopic redshifts● Low-z (z~0) [comparison]☀ Sloan Digital Sky Survey (SDSS, 5-bands)☀ 235 ETGs with log(M＊/M⦿)>10.3

3 arcsec(1arcsec~8kpc @z~1)

Selected from similar clusters to high-z
Spectroscopy by SDSS

Redshift: 0.02 < z < 0.05 (Comparable PSF size to the high-z sample)

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5.1 Example of Isophote Shape Measurements

Boxy

Boxy
Disky

High-z

Disky

Low-z

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5.2 a4 Parameter on Mass-Size Plane

Capperalli+13

Angular momentum● Massive end of ETGs is dominated by boxy

galaxies at z~1 and 0● Both at z~1 and 0, main population of ETGs varies

Disky

Low z

Figure 8. Galaxy stellar rotation on the MP projections. Same as in Fig. 1, with colours indicating the specific angular momentum parameter λet al. (2007), as given in Paper III, de-projected to an edge-on view according to the JAM inclination (Paper XV). Top panels: all ATLAS
included. A clear transition in the mean galaxy rotation is evident above MJAM ! 2 × 1011 M" , with the population becoming entirely domrotators. Bottom panels: only the slow rotators are shown. They seems to define a sequence in the MP, and they show a decrease in the rotation eMJAM ! 2 × 1011 M" , where only the slow rotators with the lowest λR are present.

the galaxies parameter space is fully sampled above the mass selection limit Mstars ! 6 × 109 M" of the ATLAS3D survey, below
this limit the data are heterogeneous. A much improved coverageof these parameters will soon be provided by the Next Generation
Virgo Cluster Survey (Ferrarese et al. 2012) as shown in Ferrarese(2012).
4 S Y S T E M AT I C VA R I AT I O N O F T H E I M F(galaxy stellar mass)

2016年6月1日水曜日

Although the IMF variation could have been included among theother galaxy observables described in Section 3, we keep the IMF

Boxy(half-light radius)from disky to boxy along constant σ at a criticalstellar mass of log(M＊/M⦿)~11.5

emphasis on the modelling assumptions that went instudies.

4.1 Summary of previous IMF results
4.1.1 IMF of the Milky Way

The stellar IMF describes the distribution of stellar ma
population formed. Nearly every aspect of galaxy form
requires a choice of the IMF to calculate predictio145.3 Relation between a4, Mass, and Size☀ Disky ETGs are frequent (and most disky) aroundlog(M＊/M⦿)~10.5, but rare in the massive end(half-light radius)(galaxy stellar mass)☀ Boxy ETGs appear in all stellar mass ranges

Boxy
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Disky

BoxyDisky15

5.4 Disky-to-total ETG Fraction at z~1 and 0with increasing stellar mass
in high-z and low-z sample.

☀ Disky fraction of high-z andlow-z sample is consistentin all M＊ bins

☀ We do not ﬁnd signiﬁcantevolution in the fraction☀ Isophote shapes & dynamical

properties of ETGs arecharacterized at z>12016年6月1日水曜日(disky-to-total fraction)☀ Disky fraction decreases(galaxy stellar mass)

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from http://mnras.oxfordjournals.org/ at University of Tokyo Library on August 27, 2014

6 Discussion● Size & morphological evolution of intermediate mass ETGs in cluster
eFieldCluster
Field−4.7 ± 0.2−5.75 ± 0.02
−5.79 ± 0.02

+0.47 ± 0.07
+0.57
+0.57

0.19
0.21
0.20

MassRedshift

Nclusterlog(M/M" ) ≥ 10.5

NfieldKSKuiper

0.7 ≤ z < 0.91301230.05
0.140.9 ≤ z < 1.1
1350.060.25
Disk-likeETGs at96z~1(Cerulo+14)
1.1 ≤ z < 1.6941250.030.29

Downloaded from http://mnras.oxfordjournals.org/ at University of T

[0.9, 1.1]
Cluster−4.8 ±favors
0.3+0.48 ± 0.08
0.19
inz<1☀ Constant disky fraction
Field−5.8 ± 0.2+0.57 ± 0.07
0.19
Cluster−5.75 ± 0.02
+0.57
0.18
less violent processes thanmajor
Field
−5.83
± 0.02+0.57
0.20[1.1, 1.6]
Cluster−3.3 ± 0.3+0.34 ± 0.10
0.25
Field
−5.2
± 0.3+0.50 ± 0.10
0.24
mergers for the main causeoftheCluster−5.78 ± 0.03
+0.57
0.24
Field
−5.89 ± 0.02+0.57
0.23
evolution of cluster ETGs

215

Table 9. Results of KS and Kuiper statistical tests applied to field andcluster ETGs mass-normalized radius distributions for different redshiftbins. Ncluster and Nfield indicate, respectively, the number of cluster galaxies
and the number of field galaxies in each sample.

Median Galaxy Size

Table 8.
Fit parametersof the MSRandfor field and cluster galaxies as☀ Cluster ETGs at z~1issmallerlog(R /kpc) = κ + β × log(M/M" ) with free slope and fixed slope
β = 0.57.
more disk-like than those at z~0Redshift
Environment
κ ± #κ
β ± #βσ(Delaye+14, Cerulo+14,De Propris+15)[0.7, 0.9]
Cluster−5.2 ± 0.3+0.52 ± 0.08
0.22

MSR in different environments

low enough (P < 0.05), to clearly state that the two distributions
are different.
In order to estimate the mean sizes at a given redshift, the size
distributions for cluster and field galaxies are fitted with a modelin which log (γ ) follows a skew-normal distribution, as previously
done by Newman et al. (2012). The best-fitting models are overplotted in Fig. 12.
This model has the advantage of better describing eventual asymFigure A1. Morphologically classified red sequence galaxies in the central region (i.e. within 0.6 Mpc from the cluster centre). Pos
metries in the size distribution. The skew normal distribution has(photometricand/or spectroscopic)of theeachobjectdeviation
are listed in Table 3. The image cutouts were taken from the HST/ACS F850LP image
indeedthree parameters:
the mean $log(γ )%,standardmorphologicalclassification(seeskewness:Sections 4.4.1 and 4.4.2).
and ainshapeparameter s thatis related to theσfieldlog(γ ) ,used2
1 − (log(γ )−ψ)2ω2P (log(γ )) =eωπ

2016年6月1日水曜日! s( log(γ )−ψ )
ω−∞

2− t2

edt.

(6)

Redshift

We then estimate $log (γ )% at a given redshift as the meanof the best-fitting skew
normal distribution,
which is given by
Figure 13. Evolution of $log (γ )% for passive ETGs with log(M/M" ) ≥√√22/π inwhere= s/classified
1 region+ s . Uncertainties$log(γ)% = ψA1.
+galaxies
ωδMorphologically
10.5fromin(redcircles)
and in(i.e.
thePosition
field(blue andtriangles).
Thepoints
Figureredgalaxies
inclusters
thethecentral
regionwithin0.6
Mpc
fromtheat cluster centre). P
Figure A1. Morphologically classified red
sequencetheδ central(i.e.sequence
withinon0.6
Mpc
clustercentre).
redshift17

7 Summary & Future Work
●Summary☀ We have measured and compared isophote shapes of cluster ETGs

at z~1 and 0.

☀ We ﬁnd similar dependence of isophote shape parameter on M＊and rh at z~1 and 0.

☀ Disky ETG fraction is consistent between z~1 and 0, although theuncertainty is large due to the still small sample size.

●Future work

☀ What about environmental eﬀect at high redshift?

☀ Isophote shapes of ETGs at even higher redshift (e.g., z~2)

3D-HST/CANDELS for ﬁeld ETGs at z<2?
New HST Cluster Supernova Survey at z~1-2 (See Change)

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