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dark-cosmology.dk /~pela

Lyman α — The Great Escape. Peter Laursen – Paris, 2009. Dark Cosmology Centre | Niels Bohr Institutet | Københavns Universitet. www.dark-cosmology.dk /~pela. Ly  escape from high- z galaxies. Why? What? How?. Gas density and temperature. Dust density and cross-section.

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dark-cosmology.dk /~pela

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  1. Lyman α — The Great Escape Peter Laursen – Paris, 2009 Dark Cosmology Centre| Niels Bohr Institutet | Københavns Universitet www.dark-cosmology.dk/~pela

  2. Ly escape from high-z galaxies Why? What? How?

  3. Gas density and temperature • Dust density and cross-section Ly escape from high-z galaxies • Analytical attempt (Neufeld 1990)

  4. Multiphase medium? Neufeld (1991); Hansen & Oh (2006) Ly escape from high-z galaxies • – Why does Ly escape after all?

  5. Ly escape from high-z galaxies • – Why does Ly escape after all? • Outflow? Kunth et al. (1999); Verhamme et al. (2006); Östlin et al. (2008)

  6. Ly escape from high-z galaxies • – Why does Ly escape after all? • Ionized holes? Kunth et al. (2003); Hayes et al. (2007)

  7. Ly escape from high-z galaxies • – Why does Ly escape after all? • Ionized cones + • viewing angle? Tenori-Tagle et al. (1999); Mas-Hesse et al. (2003)

  8. Numerical approach • Cosmological N-body + hydro simulation • + LyRT on AMR grid with dust

  9. Dust Four important quantities: • Cross-section:d() • Density:nd • Albedo: A • Phase function:P() AVNH Pei (1991) + Weingartner & Draine (2001) + Gnedin et al. (2008) e.g. Bohlin, Savage & Drake (1978)

  10. Dust Four important quantities: • Cross-section:d() • Density:nd • Albedo: A • Phase function:P()

  11. Dust Four important quantities: • Cross-section:d() • Density:nd • Albedo: A • Phase function:P()

  12. 10-4 ≥ fion ≥ 1 Dust Four important quantities: • Cross-section:d() • Density:nd • Albedo: A • Phase function:P()

  13. Dust Four important quantities: • Cross-section:d() • Density:nd • Albedo: A • Phase function:P() Calzetti et al. (1995); Lillie et al. (1976); Li & Draine (2001) ALy = 0.32 gLy = 0.73

  14. MOCALATA • Emit photon • Propagate thru ISM • Interact with • gas or dust • New and ñ • In each cell: • LLy, T, vbulk, nHI, nHII, ZC,N,O,Mg,Si,S,Ca,Fe • ✞ • New ñ • Scatter/absorb • Escape

  15. Results Surface brightness map: Without scattering

  16. Results Surface brightness map: With scattering and dust; luminous regions affected more

  17. Results  Surface brightness profile: Prominent features smoothed out

  18. Results Surface brightness profile: Dust helps to make profile looks more extended

  19. Results Surface brightness profile: Dust helps to make profile looks more extended Fynbo et al. (2003)

  20. Results Spectrum: Escape fraction smallest in the wings

  21. Results fesc(Mvir): Escape fraction decreases with galactic mass

  22. IGM transmission

  23. IGM transmission z = 3.6 z = 5.7 z = 6.3 Songaila (2004)

  24. IGM transmission z = 3.6 z = 5.7 z = 6.3

  25. Summary • Many factors help facilitating the escape of Ly • Spectrum affected in a highly non-grey fashion • fesc decreases with increasing Mvir • Dust makes SB profile even more extended • Problem can be inversed: Predict results of future observations (e.g. Ultra-VISTA) • You cannot escape the raptor

  26. Summary • Many factors help facilitating the escape of Ly • Spectrum affected in a highly non-grey fashion • fesc decreases with increasing Mvir • Dust makes SB profile even more extended • Problem can be inversed: Predict results of future observations (e.g. Ultra-VISTA) • You cannot escape the raptor

  27. Summary • Many factors help facilitating the escape of Ly • Spectrum affected in a highly non-grey fashion • fesc decreases with increasing Mvir • Dust makes SB profile even more extended • Problem can be inversed: Predict results of future observations (e.g. Ultra-VISTA) • You cannot escape the raptor

  28. Summary • Many factors help facilitating the escape of Ly • Spectrum affected in a highly non-grey fashion • fesc decreases with increasing Mvir • Dust makes SB profile even more extended • Problem can be inversed: Predict results of future observations (e.g. Ultra-VISTA) • You cannot escape the raptor

  29. Summary • Many factors help facilitating the escape of Ly • Spectrum affected in a highly non- grey fashion • fesc decreases with increasing Mvir • Dust makes SB profile even more extended • Problem can be inversed: Predict results of future observations (e.g. Ultra-VISTA) • You cannot escape the raptor

  30. Extra stuff Parameter study: Escape fraction quite insensitive to input parameters (fortunately/unfortunately)

  31. Extra stuff Parameter study: Escape fraction quite insensitive to input parameters (fortunately/unfortunately)

  32. Extra stuff Parameter study: Escape fraction quite insensitive to input parameters (fortunately/unfortunately)

  33. Extra stuff Simulation parameters (in case of obnoxious question):

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