z~1のフィールド早期型銀河のEarly-type Galaxies (ETGs)

等面輝度形状について
Isophote Shapes

満田

和真 (東京大学)

Early-type Galaxies (ETGs)
Elliptical
S0

Bulge
Random motion

Late-type Galaxies
Sab
Scd

DiskRotation

z~1のフィールド早期型銀河のEarly-type Galaxies (ETGs)

等面輝度形状について
Isophote Shapes

満田

和真 (東京大学)

Early-type Galaxies (ETGs)
Elliptical
S0

Bulge
Random motion

Late-type Galaxies
Sab
Scd

DiskRotation

Outline
1. Introduction
Dynamics and Isophote shapes of early-type galaxies
Slow and fast rotators
Boxy and disky early-type galaxies
2. Isophote Shapes of Field ETGs at z~1
No evolution in disky ETG fraction from z~1 to 0

3. Summary1.1 Dynamics of ETGs : fast/slow rotators● IFS Survey of Nearby Galaxies☀ ETG subclass: fast/slow rotators☀ ETGs become dispersion dominatedwith increasing mass

1.1 Dynamics of ETGs : fast/slow rotators● IFS Survey of Nearby Galaxies☀ ETG subclass: fast/slow rotators
Velocity Field

Rotation dominated= fast rotators☀ ETGs become dispersion dominatedwith increasing mass

1.1 Dynamics of ETGs : fast/slow rotators● IFS Survey of Nearby Galaxies☀ ETG subclass: fast/slow rotators
Velocity Field

Rotation dominated= fast rotators

Velocity Field

Dispersion dominated= slow rotators☀ ETGs become dispersion dominatedwith increasing mass

1.1 Dynamics of ETGs : fast/slow rotators● IFS Survey of Nearby Galaxies

Spin parameter λRotation dominated= fast rotators

Dispersion dominated= slow rotators☀ ETGs become dispersion dominatedwith increasing massrotowVelocity Field

Sl

Velocity Field

Re[kpc](half-light radius)☀ ETG subclass: fast/slow rotators

Fast rot
MJAM(stellar mass)
Capperalli+13

1.1 Dynamics of ETGs : fast/slow rotators● IFS Survey of Nearby Galaxies

Spin parameter λRotation dominated= fast rotators

Dispersion dominated= slow rotatorsrotow

Velocity Field

Sl

Velocity Field

Re[kpc](half-light radius)☀ ETG subclass: fast/slow rotators

Fast rot
MJAM(stellar mass)
Capperalli+13＊ Spin parameter λ☀ ETGs become dispersion dominatedwith increasing mass
Fi: ﬂux, Ri: radius, Vi: velocity,
σi: dispersion at a spaxel inumber density of the HAEs (Σ5th =2, 4, 6, 8, 10 Mpc ).
(A color version of this figure is available in the online journal.)

explain the evolution of the number density of red nuggets(Barro et al. 2013), the number density of massive quiescentgalaxies increases by a factor of two between z = 1 andz = 0 (Brammer et al. 2011), at which point the nuggets
would be very rare. This means that there must be another
evolutionary path to form quiescent galaxies from the majorityof star-forming Phase
galaxies. The IIsize(z<2?)
evolution during the starforming phase before they quench their star formation is also
evolutionquite important dynamical
as well as the later growthof their sizes byminor mergers. gas-poor
We find a lot of star-forming
galaxies withprocesses
extended disks at z > 2 (Figure 4). They are expected to evolve
into more massive galaxies
just rotators
following the local mass-size
Slow

1.2 TwoPhase
Scenario
forETG
Formation&Evolution
star-forming nuggets. The fundamental questions are how they

evolve afterward and what their descendants are in the presentday universe. The constant number density method is a usefulPhaseI (z>2?)
approachwith which we can link high-redshift galaxies tolocal galaxies (e.g., Leja et al. 2013). As shown in Figure 1,
Bulgetheformation
completeness limit ofin
our survey almost reaches down to10M>
10M⊙ . The stellar masses of the HAEs with red clumps∗
gas-richprocesses
and the star-forming nuggets are M∗ > 1010.5 M⊙ (Figures 1and 9),which corresponds to the number density of n =Fastrotators?

Tadaki+14
Figure 11. Schematic pictures of the proposed evolutionary tracks from high-redshift, star-forming galaxies to local, massive, quiescent galaxies. Blue, red, andmagenta colors indicate star-forming, quiescent, and dusty star-forming components, respectively.
(A color version of this figure is available in the online journal.)

Evolution of dynamics of ETGs is expected in z<29We want to know dynamics of high-z ETGs

1.3 Isophote Shapes of Early-Type Galaxies: Boxy vs Disky

5EllipserΔ●Ellipse : x = a cos(θ), y = b sin(θ)(a: semi-major axis, b: semi-minor axis)●

Fourier Expansion of Δr

10IsophoteDisky0-5-10

Boxy5θ0-5Δr = Σ an cos(nθ) + Σ bn sin(nθ)

a4 < 0 : boxya4 > 0 : diskye.g., Bender&Möllenhoﬀ 87

1.3 Isophote Shapes of Early-Type Galaxies: Boxy vs Disky

5

EllipserΔ●Ellipse : x = a cos(θ), y = b sin(θ)(a: semi-major axis, b: semi-minor axis)●

Fourier Expansion of Δr

10IsophoteDisky0-5-10

Boxy5θ0-5Δr = Σ an cos(nθ) + Σ bn sin(nθ)

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

1.3 Isophote Shapes of Early-Type Galaxies: Boxy vs Disky

5EllipserΔ●Ellipse : x = a cos(θ), y = b sin(θ)(a: semi-major axis, b: semi-minor axis)●Fourier Expansion of Δr

10IsophoteDisky

0-5-10Boxy5θ

0-5Δr = Σ an cos(nθ) + Σ bn sin(nθ)

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

Disky (a4 > 0)

~ Dispersion supported~ Rotation supported

Kormendy&Bender+96● Isophote shapes (boxy vs disky) can be used
as a proxy for dynamics (slow vs fast rotation)

Dispersionlog (V / σ)*Boxy (a4 < 0)

Rotation

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

Boxy a4 / a [%]Disky1.5 Redshift Evolution of Disky ETG fraction from z~1 to 0
Mitsuda+17; Penoyre+17; Pasquali+07: z ~ 0 cluster ETGs
: z ~ 1 cluster ETGs
: z~0 simulation: z~1 simulation
evolution of fast rotator
fraction from z ~ 1 to 0ntio
RFR: fFn: folatiulasimmu0 siz=1z=● Simulation● Cluster observation

no evolution of disky ETG
fraction from z ~1 to 0
environmental eﬀect?

➥ We investigate evolution of disky fraction in normal ﬁelds

Outline
1. Introduction
Dynamics and Isophote shapes of early-type galaxies
Slow and fast rotators
Boxy and disky early-type galaxies

2. Isophote Shapes of Field ETGs at z~1
No evolution in disky ETG fraction from z~1 to 0

3. Summary2.1 z ~ 1 Field ETG Sample from Five 3D-HST Fields▹ 3451 galaxies in 0.8 < z < 1.4●Quiescent galaxy selection
with UVJ diagram●Stellar mass limit withlog(M✽/M⦿)>10▹ 1181 mass-limited quiescent galaxies●Sérsic index n ≥ 2▹ 923 Field ETGs

2.2 Measuring Isophote Shape Parameter a4① Determine isophote contours

z=1.2 boxy

z=1.0 disky

w/ HST WFC3 F160W image② Fit ellipses with Fourier deviation
Radial profiles of a4 parameter
etc… are derived.

③ Get mean a4 from radial proﬁleradial proﬁle of a4radial proﬁle of a4

Luminosity weighted mean
within 2 rPSF < r < 2 rh

2 rh

2 rpsf2 rh

rh: half-light radius

2 rpsf✻ rPSF : PSF HWHM,

2.3 Dependence of a4 Parameter on Mass and Size
● No massive (log(M＊/M⦿) > 11.5) boxy ETG in z~1 ﬁeld sample● For lower mass ETGs, smaller galaxies are more disky with

Astrophysical Journal, 834:109The(23pp),
Astrophysical2017 JanuaryJournal,10834:109 (23pp), 2017 January 10z~1 Field

z~1 Cluster

Boxy(eﬀective radius)

Diskylarger a4 value(galaxye 13. Distribution of the low- (left)Figureand high-redshift
13. Distribution(right)ofstellar
quiescentthe low- mass)(left)ETG andsamples
high-redshift
on the mass–size(right) quiescent(M*–re)ETG
plane.samples
Color codeon theindm

2.4 Disky ETG Fraction at z~1 and 0 in Diﬀerent Environment
Only two galaxies...

: z ~ 0 cluster ETGs
: z ~ 1 cluster ETGs

: z ~ 1 field ETGs
: z ~ 0 simulation: z ~ 1 simulation

tion

FR: f FRn: folati

ulasimmu0 si

z=1z=● Low mass ETGs

In z ~ 1 cluster and field,disky fraction is consistent● High mass ETGsToo small sample for z ~ 1field ETGs to compare tothe simulation

2.5 Number density of Boxy and Disky ETGsz ~ 1 ETGs (all)z ~ 0 ETGs (all): z ~ 1 disky ETG

Stellar mass function: z ~ 0 disky ETG: z ~ 1 boxy ETG: z ~ 0 boxy ETG● log(M＊/M⦿) > 11≈

N of z ~ 0 boxy ETG
N of z ~ 1 disky ETG
evolution from FR (disky)
to SR (boxy) may occur

Bundy et al., 2010 x our results

3 Summary●Introduction☀ Dynamics of early-type galaxies: slow rotators vs fast rotators☀ Isophote shape (boxy vs disky) is related to dynamics☀ Evolution from fast (disky) to slow (boxy) rotators in z<1 is predicted●Our results☀ No evolution of disky fraction in z<1 independent of environments✻ Disky fraction for z~1 ﬁeld ETGs in massive end is uncertain☀ No evolution in disky fraction is NOT inconsistent with disky (FR)to boxy (SR) evolution if the number density is taken into account.