1銀河進化 MM 2017June7@Osaka

銀河のダウンサイジング－もし超重ブラックホールが先にできたら－

Masahiro Morikawa
Ochanomizu University

Akika Nakamichi
Kyoto-Sangyo University,
Koyama Observatory

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1. Introduction – Cosmic Downsizing
Downsizing of galaxies:
Larger galaxies evolve faster (observation).
Similar to: stars, sparkling firework, nuclear fuel, …
Top-down as functional differentiation (機能分化)
Opposite to: lives, variable stars, LCDM cosmology (theory), …
Bottom-up as disordered aggregation (要素凝集)→

galaxy formation as functional differentiation !

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2. Various aspects of Cosmic Downsizing★

More massive galaxy completes the star formation fast.

Heavens et al. 2004

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More massive galaxy is redder.
i.e. more massive galaxies host older stellar populations

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More luminous AGN peaked at higher z.
i.e. More massive BH formed earlier.

LADE(Aird+ 2010)

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the mass of the typical SF galaxy grows with z.

https://arxiv.org/abs/0912.0259v2

7★ at z≲1, the number density of smaller galaxies evolves fasterFontanot et al. (2009)8★

More massive galaxy has higher M * / M h peaks earlier

Apj717 379 P. S. Behroozi 2010

9★ Galaxies evolve faster in higher density environment

Thomas et al. (2005)

10◆ DS from (L)CDM model?
Standard LCDM model:
0- Small structures form first ←”C” i.e. pressure=0, lJ- These DM halos (106 M ) merge to form galaxies(1011 M )→Quite opposite to the Downsizing!

Any bias is needed for rapid merger w/o SF at t

0.8Gy

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◆ DS from L(CDM) model
Natural solution is needed based on LCDM.
CDM…OKL…?? Is it always uniform?
1. Unstable L model based on DE=BEC
i.e. coherent classical field collapses into SMBH
2. SMBH form variety of galaxies.

z1020【Our assumption】SMBH forms first and nurtures a galaxy

12- Usually they are thought to have coevolved, but mature SMBH
appeared too early:z

6.3, M SMBH

12109 Mz

7, M SMBH

2.0

109 M

- Boson: If MM kaup

be avoided.

Xue-BingWu et al., Nature14241 etc.

c0.633Gm

De Rosa et al.2014, ApJ, 790, 145 etc. etc….

m pl 2, collapse cannot
m- cf. critical phenomena of BH: Choptuik1993, Gundlach2007

M BH(pp* )g

BEC easily collapses to form SMBH

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Updated Rees chart
DE(BEC)

SMBH

2017

Rees chart 1978
How to make SMBH

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Reversed Rees chart
How the SMBH form stars andgalaxies

Terribly Sorry, Prof. Rees!

15◆SMBH → Jet → Shock wave → SF (Inside the jet, hot)
→ Activates Jet
M BH
M BH

GC？

f ks 52 (energy balance)...prevent SF
4pcG
f ks 42 (pressure balance)...promote SF
4pG

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⇒

SF Promotion & SF Obstruction coexist !
a galaxy in Fenixcluster
H. Russell, et al.
2017
CO(3-2)integrated
intensity map(Cold gas)
&X-ray cavities(McDonald et al.
2015).
(Hot gas)

Jet

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3. SMBHFF model Our model:➢ Gas of amount Gi in the direction i (i1, 2, 3..., N covers
the whole sky) forms new stars with the rate m , and falls
toward the center, triggered by jet J from SMBH.
➢ A part of them (of ratiol ) exerts torque on the SMBH yielding
the shift of the jet direction.
➢ New gas in that direction forms new stars that fall and exert
further torquem : SFR…environmentGi (t )mcconv J (t ) Gi (t ) Gi (t )l ：acc rate…intrinsic

J (t )lJ (t )G(t)iiJ-G,Feedback modelkJ (t )

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◆ variety of galaxies

SFR

Ellipticals:…if gas exhausted
jetflippingElliptical.avi

Bulge mass

レンズ銀河

heavy

楕円銀河

Spirals:…if gas remains
jetflippingSpiral.avi
i.e.
Percolation
phase separation

不規則銀河 渦巻銀河

light

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4. Downsizing 1■■■■

The SMBH emits energetic jet that is narrow and long.
This jet heats up the ambient gas, which rapidly expands in almost the cylindrical symmetric form.
Thus the gas forms a cylindrical shock wave which propagates outward.
This shock wave compresses the ambient gas and triggers the star formation (momentum driven shock).

Shock wave from jet forms stars:

Wherecf. King
2003,2008

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Assuming,

the solution is

where
The shock wave is assumed to stop when v→

the time→

the radius:andvS

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Suppose the stars forms within this region, then

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From,
Time scale of the evolution becomes:

This is almost independent of the galaxy size. This is NOT DS.
The failuer would be the lack of the feedback eﬀect of the jet starformation.

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Typical values:< galaxy size.
→ Cylinder app. OK.
<→ gr. Neglected OKZ=2.95

For

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5. Downsizing 2 - rough estimate of feed backm J ni Gi yields the time scale of the gas depletion:

Git 2

mJ further, t 1(star formation rate mmJ

mM BH
rgas 3 / 4 M Bulge

rgas 3 / 2 Schmit law) i.e.

1.

Larger the galaxy/SMBH, more rapid formation.

2.

Denser the environment, more rapid formation.

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6. Downsizing 3 - numerical calculations,

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Time scale & Bulge mass →Larger galaxy evolves faster27-larger j, m, l , means

faster evolution.
- Elliptical evolves fasterthan Spiral.
i.e. many colliding Spirals do
not form Elliptical.

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7. Summary and prospects【conclusions】- galaxy formation based on primordial SMBH is possible- “L”CDM model → DE field decays

SMBH

Jetstars- Downsizing is naturally associated with this model.
- Origin of DS is the strong feedback J ⇔ G- Physics behind is the percolation phase separation: Ell&Sp…
- Numerical calculation is possible based on the minimal model.

33【comments】basic problem for SMBH/galaxy/DS
1.Why SMBH rapid evolution at z=7?
→ DE (if attractive BEC) can collapse to form SMBH
2.Why there is no SMBH off center?
→a SMBH forms galaxy around it

3.Why galaxies are symmetric for rotation- p ?
→ SMBH jet formed stars around it (momentumconservation)
4.Why downsizing?
→jet activity (not merger) determines the time scale