1 / 35

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.

moe
Download Presentation

dark-cosmology.dk /~pela

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. 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):

More Related