Big Bang Nucleosynthesis light elements, deuterium ... light elements, deuterium bottleneck Nuclear

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Transcript of Big Bang Nucleosynthesis light elements, deuterium ... light elements, deuterium bottleneck Nuclear

  • Nucleosynthesis Big Bang Nucleosynthesis light elements, deuterium bottleneck

    Nuclear Reactions in Stars hydrogen burning, triple-α process

  • BBN板書

  • Nuclear binding energy mi = Zmp + N mn -EB/c2

  • Stellar synthesis: pp-chain

  • Solar neutrino ppII

    ppIII

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

  • CNO cycle

  • Triple-α process 4He + 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 gas Star 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 H He+

  • Collisional excitation Most important : Hydrogen Lyman-a line

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

    Excitation to a higher level + spontaneous emission

  • Recombination p + e → H + g He+ + e → He + g He++ + e → He+ + g and similar processes for metal ions

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

  • Bremsstrahlung Ion (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 winds Radiation

  • Orion Visible IR

    Giant Molecular Cloud

  • Schmidt law in MW SF R es tim at ed fr om F IR

    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 function Pipe nebula

    Alves, Lombaridi, Lada 2007

  • Core mass function

    テキスト

    Andre et al. 2007

  • Turbulent ISM High-density clouds in a supersonic, compressible turbulence.

  • The role of blackholes

  • Jets from the center

  • Radio lobes around a BH M87

    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 Msun r

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

    MBH ~ 3x109 Msun

    FIR luminosity 1.3x1013 Lsun

  • The Eddington rate The 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>6 Li et al. 2007 Merging and gas accretion onto PopIII remnants

    Almost always at Eddington rate at z~6, to become 109Msun

  • BH feedback model