NucleosynthesisBig Bang Nucleosynthesis light elements, deuterium bottleneck

Nuclear Reactions in Stars hydrogen burning, triple-α process

BBN板書

Nuclear binding energymi = Zmp + N mn -EB/c2

Stellar synthesis: pp-chain

Solar neutrinoppII

ppIII

e+7Be → 7Li + ν (electron capture) 8B → 8Be + e+ +ν

CNO cycle

Triple-α process4He + 4He ⇄ 8Be

8Be + 4He → 12C + γ 8Be は不安定で、10-16 秒で崩壊する。その間に都合のよいエネルギーの4Heをぶつけなくてはならない（3体反応）。初期宇宙ではこの過程に至らない

In the beginning...

H, He, DM,γ

Galaxy formation✦ Formation of nonlinear “halos”

✦ Formation and evolution of a hot gas

✦ Cooling and condensation

✦ Star formation

✦ Formation of blackholes

Hierarchical galaxy formation

Evolution of a halo gasStar are formed in a cold, dense, molecular gas.

Gravity alone does not make it. Gravitational collapse compresses and heats the gas.

A mechanism to cool a gas cloud is needed.

Radiative cooling removes the excess energy

(i.e., lowers the gas pressure) and makes it possible

for the gas to cool and condense.

Radiative cooling operates only if there are coolants.

Radiative cooling

金属量HHe+

Collisional excitationMost important : Hydrogen Lyman-a line

H(n=1) + e → H(n=2) + eH(n=2) → H(n=1) + g

Excitation to a higher level+ spontaneous emission

Recombinationp + e → H + gHe+ + e → He + gHe++ + e → He+ + gand similar processes for metal ions

Each process emits photon(s) with energy of ionization potential,i.e. 13.6eV for hydrogen

BremsstrahlungIon (H+, He+, He++) + e → ion + e

g

Contribution of metals

Bottom-up scenario

Hierarchical mergers and

gas cooling, condensation

tcool < tdyn

Star-formation in a galaxy

Turbulence

Cosmic rays

Supernovae

Stellar windsRadiation

OrionVisible IR

Giant Molecular Cloud

Schmidt law in MWSFR estimated from FIR

Misiriotis et al. 2006

Kennicutt-Schmidt law

normal disk

star-burst

centers

ΣSFR (Msun/yr/pc2) = Coeff. xΣgas 1.4 (Msun/pc2)

Scalo IMF

Core mass functionPipe nebula

Alves, Lombaridi, Lada 2007

Core mass function

テキスト

Andre et al. 2007

Turbulent ISMHigh-density clouds in a supersonic, compressible turbulence.

The role of blackholes

Jets from the center

Radio lobes around a BHM87

Energy input from the central blackhole.

Initially as a dipolar relativistic jets

Cocoons and bubbles are formed

BH in Milky Way!

HST monitoring

The Magorrian relation

M-σ relation at small M

Barth, Greene, Ho 2005

How can a BH influence the host galaxy ?

The Schwarzschild radius for a BH with M is r = 2GM / c2

r ~ 3 km for 1 Msunr << 1 pc even for 108 Msun

The radius of gravitational influence isr BH = GM/σ2 = 10.8 pc (M/108) (σ/200 km/sec)-2

Quasar SDSS J1148+5251VLACO(3-2)@z=6.42 (870 Myr)

MBH ~ 3x109 Msun

FIR luminosity 1.3x1013 Lsun

The Eddington rateThe Eddington luminosity

The radiative efficiency

Salpeter time: M/Mdot ~ 4 x 107 year　　　 　 f for ε = 0.1.

L = ε M c2

宇宙初期のSMBH宇宙年齢7億7千万年の頃に存在した、太陽の20億倍のブラックホール

VLT FORS + Gemini NIRS

Quiz 4: 時間リミットz=7にあるSMBHの何が問題なのか

計算して理解しよう。初期宇宙ではブラックホールは全てEddington限界で成長するという（やや無理な）仮定をたてる。radiative efficiency εr = 0.1 として、Salpeter time はtBH = 4 x 107 年。この時間でBHは質量をもとの e 倍にすることができる。始めの種として、大質量星の重力崩壊によりできるBHを考え、その質量を10 Msunとする。10 Msun のBHが降着により 3x109 Msun になるには（つまり3x108倍質量を増やすには）何年必要か。

SMBH formation @ z>6Li et al. 2007Merging and gas accretion ontoPopIII remnants

Almost alwaysat Eddington rateat z~6, to become 109Msun

BH feedback model