1 / 60

梅村　雅之 筑波大学　物理学系　（計算物理学研究センター）

銀河形成. 梅村　雅之 筑波大学　物理学系　（計算物理学研究センター）. I. 銀河形成の初期条件／境界条件 II. 第一世代天体 II Ｉ . 宇宙再電離 IV. 銀河形成と進化. 赤方 偏移. 天体の起源. 物質の起源. 時間. 量子ゆらぎ. 量子宇宙. 10 -44 秒. 10 30. 古典ゆらぎ （ハリソン－ゼルドビッチスペクトル）. ダークマター生成 陽子・中性子（バリオン）形成. 密度ゆらぎ （宇宙背景放射ゆらぎ）. 軽元素合成 （ p,n,He,D,T,Be,Li ）. 10 3. 50 万年. 宇宙再結合.

hashim
Download Presentation

梅村　雅之 筑波大学　物理学系　（計算物理学研究センター）

An Image/Link below is provided (as is) to download presentation Download Policy: Content on the Website is provided to you AS IS for your information and personal use and may not be sold / licensed / shared on other websites without getting consent from its author. Content is provided to you AS IS for your information and personal use only. Download presentation by click this link. While downloading, if for some reason you are not able to download a presentation, the publisher may have deleted the file from their server. During download, if you can't get a presentation, the file might be deleted by the publisher.

E N D

Presentation Transcript

  1. 銀河形成 梅村　雅之 筑波大学　物理学系　（計算物理学研究センター） I. 銀河形成の初期条件／境界条件 II. 第一世代天体 IIＩ. 宇宙再電離 IV. 銀河形成と進化

  2. 赤方 偏移 天体の起源 物質の起源 時間 量子ゆらぎ 量子宇宙 10-44秒 1030 古典ゆらぎ （ハリソン－ゼルドビッチスペクトル） ダークマター生成 陽子・中性子（バリオン）形成 密度ゆらぎ （宇宙背景放射ゆらぎ） 軽元素合成 （p,n,He,D,T,Be,Li） 103 50万年 宇宙再結合 Dark Age 重元素合成 超新星爆発 α元素, r-,s-過程元素, ... 第一世代天体 1億年 15 宇宙再電離 銀河形成 SNII α元素, r-,s-過程元素, ... （クェーサー，星，BH） SNIa 鉄族元素, ... 5 銀河団 太陽系 140億年 ０ 有機物 宇宙大規模構造 生命 （現在）

  3. I. 銀河形成の初期条件と境界条件 1. Cosmological Parameters 2. Fluctuation Spectrum 3. Reionization

  4. COBE =7°– 180° WMAP =0.2°– 180°

  5. WMAP 理論

  6. Cosmological Parameters (CDM Universe) Fluctuation Spectrum (CDM)

  7. Thomson optical depth (Reionization)

  8. First Objects (Pop III) CMB n=1 gg Mgal Mcluster CDM Density Fluctuations Neutral Ionized 30 1 10 Dwarf Galaxies 1+zc Galaxies Clusters 1

  9. II. 第一世代天体 1. H2 Formation 2. First Objects 3. First Stars

  10. 初期ゆらぎの重力収縮 ジーンズ条件（重力エネルギー＞熱エネルギー） 密度上昇　← 冷却過程で支配される  現在の銀河 重元素冷却，ダスト冷却  第一世代天体 星が生まれていない　⇒　重元素がない 重元素以外の冷却　⇒　水素分子

  11. e- p + - e- p  水素分子形成 電気双極子モーメント=0　⇒　H+H→H2+ 禁止 H ３体反応 （高密度） H2 e.g. 宇宙晴れ上がり時 （低密度） 陽子反応 (z100) 電子反応 (z100) H2 H2 H H H- H+

  12. Formation of Pop III Stars Reaction 1: e-+ H  H- + h  H- + H  H2 + e- (z100) Reaction 2: p + H  H2 ++ hH2 ++ H  H2+ p (z100) Matsuda, Sato, & Takeda (1969, Prog. Theor. Phys., 42, 219) Non-equilibrium processes equilibrium non-equilibrium Susa et al. (1998, PTP, 100, 63) IGM (residual ion. e10-5): H210-5 No shock ion. (Ts<104K): H2 10-4 – 10-3 Shock ion. (Ts >104K): H210-3 –10-2

  13. First Object Mass Yoshida et al. (2003, ApJ, 592, 645) 60million particles 100M per gas particle Mhalo  106 M

  14. Pop III Stars Gravitational Energy＝Internal Energy 3D (sphere)M = const. 1D (sheet)M/r2 = const. 2D (cylinder)M/r = const. Nishi et al. (1998, PTP, 100, 881)

  15. Fragmentation of Cylinder Rate equation e-, H, H+, H-, H2, H2+, D, D+, HD, He, He+, He++ Level population (regarding level j ) Ckj Akj j Ajk Cjk Bjk Radiation transfer (or Escape probability ) Cooling function

  16. Critical Density ncrit Ckj Akj j Ajk Cjk Ckj Ckj j Cjk Cjk

  17. Fragment Mass at ncrit H2 cooling A20 ~ 2.94  10-11

  18. Opacity Limited Mass Uehara et al. (1996, ApJ, 473, L95) Rees (1976, MNRAS, 176, 483) (Chandrasekhar mass) Nakamura & Umemura (2001, ApJ, 548, 19) 2D Simulation

  19. =0.1 Nakamura & Umemura (2001, ApJ, 548, 19) Initial high density leads to low fragment mass.

  20. （M） Pop III Star IMF Fragment mass criterion + CDM spectrum Nakamura & Umemura (2001, ApJ, 548, 19)

  21. HD Molecule Cooling UV ionization(e.g. Corbelli et al. 1998; Susa & Umemura 2000) Shock ionization(e.g. Shapiro & Kang 1987; Ferrara 1998) High H2 abundance HD: A10 ~ 5.12  10-8 c.f. H2: A20 ~ 2.94  10-11 HD Cooling critical density:

  22. Opacity Limited Mass HD cooling Uehara & Inutsuka 2000, ApJ, 531, L91 Nakamura & Umemura (2002, ApJ, 569, 549)

  23. Pop III Pop I Mcore10-3 M 10-3 M Mfrag 103M>0.1M M10-3 M/yr10-5 M/yr . Protostellar Collapse Omukai & Nishi 1998, ApJ, 508, 141; Omukai 2000, ApJ, 534, 809 2nd core Z/Z 1st core grain temperature Conversion of Kelvin-Helmholtz Contraction

  24. Envelope: 103 M Core:10-2 M Infall Rate: 10-2 M/yr

  25. SN Explosion of Massive Stars Umeda & Nomoto 2002, ApJ, 565, 385

  26. End-Product of Massive Stars Heger et al. 2003, ApJ, 591, 288 Type I Collapsar: BH formation by core collapse Type II Collapsar: BH formation by fallback caused by SN shock Type III Collapsar: BH formation without proto-neutron star formation JetSN: Hypernova GRB: long GR burst（a portion of Jet SNs） Z/Z 1 Pair 0

  27. III. 宇宙再電離 1. Self-Shielding 2. Reionization History 3. UVB History

  28. Propagation of Ionizing Front Yoshida et al. 2003 Stars in molecular gas clouds HII regions + soft UV

  29. Early Reionization Process Ciardi, Ferrara & White 2003, MNRAS, 334, L17 z = 17.6 z=15.5 z=13.7 Larson IMF (Top-heavy) Salpeter IMF

  30. Self-Shielding Tajiri & MU (1998, ApJ, 502, 59) UV background: I0=I21 10-21(ν/νL)- erg s-1 cm-2 Hz-1 str-1 =1-5 Radiation transfer Ionization equilibrium

  31. Spherical Top-Hat Cloud Numerical Results (n>ncrit ; HI>0.1) Strömgren approximation Number of incident UV Number of recombination photons per second to excited states per second = Strömgren approximation underestimates the self-shielding.

  32. Reionization History in Inhomogeneous Universe Nakamoto, MU, Susa (2001, MNRAS, 321, 593) 3次元輻射輸送方程式 自由度: 3D space, 2D directions, 1D frequency = 6D Space: N3＝1283 in (8Mpc)3 Directions:NθNφ＝128 2 Frequency:Nν＝6 lines for H & He, analytic integration for continuum • Total operations:f NiterN3NθNφNν＝11.4 Tflops・hr ( f 2000, Niter=100) • Performed with the CP-PACS (614GFLOPS)

  33. Zel’dovich approx. withΩCDM=0.95, ΩBaryon=0.05, σ8=0.6, h=0.5 Isotropic UV: I0=I21 10-21(ν/νL)-1 erg s-1 cm-2 Hz-1 str-1 N3＝1283 in (8Mpc) 3 Radiative Transfer Ionization Equilibrium

  34. QSO

  35. Nakamoto, MU, Susa (2001, MNRAS, 321, 593) I21=0.1 3億年 5億年 7億年 10億年

  36. Self-Shielding （自己遮蔽） Shadowing （日陰効果） Z=9 Z=7 Z=5

  37. Cosmic Reionization History and Effect of Inhomogeniety

  38. Thomson Optical Depth (Poster: Hiroi, MU, Nakamoto) 0.2 0.1 I21 > 0.1 at z >14 optical depth τe(z) 0.04 ：I21=0.1 ：I21=10-2 0.02 ：optically thin 10-2 4 8 12 16 20 z

  39. Redshift z<4 z≈4 4<z<6 z>14 z≈20 Method proximity effect DA DA te te I21 0.5±0.1 Giallongo et al. 1996 I21≈1 I21≈0.1 I21 > 0.1 I21 ≥ 1 free Evolution of UVB Intensity I21 1 WMAP 0.5 proximity effect Ly  continuum depression 0.1 4 6 14 20 Redshift

  40. IV. 銀河形成と進化 1. Formation of Subgalactic Objects 2. Formation of Normal Galaxies 3. Galactic Evolution

  41. First Objects (Pop III) CMB n=1 gg Mgal Mcluster CDM Density Fluctuations Neutral Ionized 30 1 10 Dwarf Galaxies 1+zc Galaxies Clusters 1

  42. ...Werner band Solomon Process Lyman-Werner band : 11.26-13.6 eV 15% of excited states decay to the continuuum (v>15)  photodissociation (Solomon process) 85% populate vib-rotational levels of v14  fluorescence lines

  43. Rate coefficient of Solomon process Self-shielding(Draine & Bertordi 1996, ApJ, 468, 269)

  44. Radiation Hydrodynamical Collapse of Subgalactic Clouds under UVB Kitayama, Susa, MU, Ikeuchi 2001, MNRAS, 326, 1353 UV: Radiative transfer including self-shielding for LW band Spectral shape : power-law, Planck Dynamics: Spherical Lagrangian Hydrodynamics H2 : Non-equilubrium chemistry including H- photo-detachment H2+ photo-dissociation

  45. self-shielding UV Effects Kitayama et al. 2001, MNRAS, 326, 1353 Dynamics: Spherical hydrodynamics UV: Radiative transfer H2 : Non-equilubrium chemistry

  46. Substructure Problem Moore et al. 1999, ApJ, 524, L19 Cluster Halo Moore et al. 1999 Galactic Halo 20 times smaller than expected

  47. 再電離宇宙における矮小銀河形成 （Susa & MU 2004, ApJ, in press）

  48. dissipationless GF dissipational GF Elliptical Galaxies Spiral Galaxies 銀河形態の起源 • Merger Hypothesis Disk major merger  Ellipticals N-body, Hydro-simulation, Semi-analytic • Monolithic Bifurcation (Larson’s paradigm) Protogalactic clouds

  49. GC3 - Grand Challenge Cosmology Consortium- Cluster Simulations on the PSC Cray T3E John Dubinski

More Related