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
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