www.dark-cosmology.dk/~pela

Lyman α — The Great Escape

Dark Cosmology Centre | Niels Bohr Institutet | Københavns Universitet

DFS Annual Meeting 2009

Supervisors: Anja C. Andersen &

Jesper Sommer-Larsen

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Lyα escape from high-z galaxies

Why?

What?

How?

Lyα is a powerful probe of the early Universevery

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Lyα escape from high-z galaxies

Why?

What?

How?

Lyα is a powerful probe of the early Universe very

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Lyα escape from high-z galaxies

Analytical attempt (Neufeld 1990)

Gas density and temperature Dust density and cross-section

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Neufeld (1991); Hansen & Oh (2006)

Multiphase medium?

Lyα escape from high-z galaxies– Why does Lyα escape after all?

Kunth et al. (1999); Verhamme et al. (2006); Östlin et al. (2008)

Outflow?

Tenori-Tagle et al. (1999); Mas-Hesse et al. (2003);Ionized holes?

Kunth et al. (2003); Hayes et al. (2007)

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Numerical approachCosmological N-body + hydro simulation+ Lyα RT on AMR grid with dust

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DustFour important quantities:

• Density: nd

• Cross-section: d()

• Albedo: A• Phase function: P()

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DustFour important quantities:

• Density: nd

• Cross-section: d()

• Albedo: A• Phase function: P()

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Dust

Pei (1991) + Weingartner & Draine (2001) + Gnedin et al. (2008)

Four important quantities:

• Density: nd

• Cross-section: d()

• Albedo: A• Phase function: P()

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Dust

Calzetti et al. (1995); Lillie et al. (1976); Li & Draine (2001)

Four important quantities:

• Density: nd

• Cross-section: d()

• Albedo: A• Phase function: P()

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Monte Carlo

In each cell:LLyα, T, vbulk, nHI, nHII, ZC,N,O,Mg,Si,S,Ca,Fe

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Monte Carlo

In each cell:LLyα, T, vbulk, nHI, nHII, ZC,N,O,Mg,Si,S,Ca,Fe

Emit photon

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Emit photon

Monte Carlo

In each cell:LLyα, T, vbulk, nHI, nHII, ZC,N,O,Mg,Si,S,Ca,Fe

Propagate thru ISM

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Monte Carlo

In each cell:LLyα, T, vbulk, nHI, nHII, ZC,N,O,Mg,Si,S,Ca,Fe

Propagate thru ISM

Interact withgas or dust

Emit photon

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Monte Carlo

In each cell:LLyα, T, vbulk, nHI, nHII, ZC,N,O,Mg,Si,S,Ca,Fe

Interact withgas or dust

New and ñ

Propagate thru ISM

Emit photon

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Monte Carlo

In each cell:LLyα, T, vbulk, nHI, nHII, ZC,N,O,Mg,Si,S,Ca,Fe

New and ñ

Scatter/absorb

Interact withgas or dust

Propagate thru ISM

Emit photon

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Monte Carlo

In each cell:LLyα, T, vbulk, nHI, nHII, ZC,N,O,Mg,Si,S,Ca,Fe

Scatter/absorbNew ñ

New and ñ

Interact withgas or dust

Propagate thru ISM

Emit photon

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Monte Carlo

In each cell:LLyα, T, vbulk, nHI, nHII, ZC,N,O,Mg,Si,S,Ca,Fe✞Scatter/absorbNew ñ

New and ñ

Interact withgas or dust

Propagate thru ISM

Emit photon

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Monte Carlo

In each cell:LLyα, T, vbulk, nHI, nHII, ZC,N,O,Mg,Si,S,Ca,Fe

Escape

✞Scatter/absorbNew ñ

New and ñ

Interact withgas or dust

Propagate thru ISM

Emit photon

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ResultsSurface brightness map

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ResultsSurface brightness profile

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ResultsSurface brightness profile: dust helps to make profile look more extended

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ResultsSpectrum

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Resultsfesc(Mvir)

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Songaila (2004)

IGM transmission

z = 6.3

z = 5.7

z = 3.6

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IGM transmission

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IGM transmission

z = 6.3

z = 5.7

z = 3.6

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Summary• Many factors help facilitating the escape of Lyα• 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

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Summary• Many factors help facilitating the escape of Lyα• 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

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Summary• Many factors help facilitating the escape of Lyα• 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

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Summary• Many factors help facilitating the escape of Lyα• 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

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Summary• Many factors help facilitating the escape of Lyα• 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