www.dark-cosmology.dk/~pela

1
Lyman a 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
Ly? escape from high-z galaxies
Analytical attempt (Neufeld 1990)
4
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
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
In each cell LLy?, T, vbulk, nHI, nHII,
ZC,N,O,Mg,Si,S,Ca,Fe
New ??and ñ
?
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
(No Transcript)
23
(No Transcript)
24
IGM transmission
25
IGM transmission
z 3.6
z 5.7
z 6.3
Songaila (2004)
26
IGM transmission
z 3.6
z 5.7
z 6.3
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
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
31
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
32
Extra stuff
Parameter study Escape fraction quite
insensitive to input parameters
(fortunately/unfortunately)
33
Extra stuff
Parameter study Escape fraction quite
insensitive to input parameters
(fortunately/unfortunately)
34
Extra stuff
Parameter study Escape fraction quite
insensitive to input parameters
(fortunately/unfortunately)
35
Extra stuff
Simulation parameters (in case of obnoxious
question)