Lighting up the light-shedding of illuminated enlightenment of bright light
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Lighting up the light-shedding of illuminated enlightenment of bright light – or – Modeling Lya spectra. Peter Laursen, with Jens-Kristian Krogager & Johan Fynbo. | Niels Bohr Institutet | Københavns Universitet. www.dark-cosmology.dk /~pela. QSO2222-0946.

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Dark cosmology dk pela

Lighting up the light-shedding of illuminated enlightenment of bright light

– or –

Modeling Lya spectra

Peter Laursen,

with Jens-Kristian Krogager & Johan Fynbo

| Niels Bohr Institutet | Københavns Universitet

www.dark-cosmology.dk/~pela


Dark cosmology dk pela

QSO2222-0946

HST/UVIS with the F606W filter


Dark cosmology dk pela

QSO2222-0946

VLT/X-Shooter (UVB arm)


Dark cosmology dk pela

QSO2222-0946

VLT/X-Shooter (UVB arm)


Dark cosmology dk pela

Modeling Lya lines

…has been done before

Verhamme et al. (2008) with MCLYA


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The model

MoCaLaTA


Dark cosmology dk pela

Input parameters

Geometry:

• Radius

• Number of clouds

• Cloud size distribution

MoCaLaTA

rgal

Ncl

rcl,min; rcl,max; β

State of the clouds and the intercloud medium:

• Neutral hydrogen density

• Temperature

• Dust density ⇐ metallicity

nHI,cl; nHI,ICM

THI,cl; THI,ICM

ZHI,cl; ZHI,ICM

Kinematics:

• Cloud velocity dispersion

• Outflow velocity

sV,cl

Vout

Emission:

• Intrinsic line width

• Emission scale length

• Emission site/cloud correlation

• Systemic redshift

sline

Hem

Pcl

z


Dark cosmology dk pela

Input parameters

rgal

Ncl

rcl,min; rcl,max; β

10 kpc

Kim+ 03 (LMC)

∼105

Dickey & Garwood 89; Williams & McKee 97

10–100 pc;

–1.6

nHI,cl; nHI,ICM

THI,cl; THI,ICM

ZHI,cl; ZHI,ICM

sV,cl

Vout

sline

Hem

Pcl

z


Dark cosmology dk pela

Input parameters

rgal

Ncl

rcl,min; rcl,max; β

0.2–0.5 cm-3 from e.g. Carilli+ 98; Ferrière 01; Gloeckler & Geiss 04 (MW)

10 kpc

∼105

10–100 pc;

–1.6

ntot = 10–3–10–2 cm-3 (Dopita & Sutherland 03; Ferrière 01),

xHI,ICM ∼ 10–8–10–5 (House 64; Sutherland & Dopita 93),

plus residual diffuse HI clouds.

nHI,cl; nHI,ICM

THI,cl; THI,ICM

ZHI,cl; ZHI,ICM

0.3 cm–3;

10–10–10–5 cm–3

e.g. Brinks+ 00; Tüllmann+ 06,08

106 K

104 K;

0.31 Z

From Zn, Si, and Fe abs. lines, as well as from

[OII]/[OIII] and [NII]/Ha (R23 and N2 methods)

sV,cl

Vout

sline

Hem

Pcl

z


Dark cosmology dk pela

Input parameters

rgal

Ncl

rcl,min; rcl,max; β

10 kpc

∼105

10–100 pc;

–1.6

nHI,cl; nHI,ICM

THI,cl; THI,ICM

ZHI,cl; ZHI,ICM

0.3 cm–3;

10–10–10–5 cm–3

104 K;

106 K

0.31 Z

sV,cl

Vout

115±18 km s–1

From abs. line widths

100–200 km s–1

sline

Hem

Pcl

z


Dark cosmology dk pela

Input parameters

rgal

Ncl

rcl,min; rcl,max; β

10 kpc

∼105

10–100 pc;

–1.6

nHI,cl; nHI,ICM

THI,cl; THI,ICM

ZHI,cl; ZHI,ICM

0.3 cm–3;

10–10–10–5 cm–3

104 K;

106 K

0.31 Z

sV,cl

Vout

115±18 km s–1

100–200 km s–1

sline

Hem

Pcl

z

130 km s–1

From [OII], [OIII], Ha, and Hb

2.1 kpc

From HST imaging (reff = 1.09 kpc)

n/a

0.2–0.5

2.35

From [OII], [OIII], Ha, and Hb


Dark cosmology dk pela

Input parameters

rgal

Ncl

rcl,min; rcl,max; β

Set by observations

10 kpc

∼105

Standard values

10–100 pc;

–1.6

Fitted for

nHI,cl; nHI,ICM

THI,cl; THI,ICM

ZHI,cl; ZHI,ICM

0.3 cm–3;

10–10–10–5 cm–3

104 K;

106 K

0.31 Z

sV,cl

Vout

115±18 km s–1

100–200 km s–1

sline

Hem

Pcl

z

130 km s–1

2.1 kpc

n/a

2.35


Dark cosmology dk pela

Finding the best fit

1. Run trial models to get a rough fit

⇒ Ncl∼ 105; Vout∼ 150 km s-1

2. Run grid with Ncl∈ [104.5,105.5] and

Vout∈ [100,200] km s-1


Dark cosmology dk pela

Finding the best fit

1. Run trial models to get a rough fit

⇒ Ncl∼ 105; Vout∼ 150 km s-1

2. Run grid with Ncl∈ [104.5,105.5] and

Vout∈ [100,200] km s-1

3. Fit skewed Gaußians

4. Measure

a) Red peak FWHM

b) Peak separation

c) Peak height ratio

d) Peak flux ratio


Dark cosmology dk pela

Finding the best fit

1. Run trial models to get a rough fit

⇒ Ncl∼ 105; Vout∼ 150 km s-1

2. Run grid with Ncl∈ [104.5,105.5] and

Vout∈ [100,200] km s-1

3. Fit skewed Gaußians

4. Measure

a) Red peak FWHM

b) Peak separation

c) Peak height ratio

d) Peak flux ratio

5. Calculate number of std. dev.sbetween

synthetic and observed spectra

6. Identify best fitting model

and those for which all four fitting

parameters fall within 1σ


Dark cosmology dk pela

Results

Best-fitting models give:

Vout= 160 km s-1

log(NHI/cm-2) = 20.23

Ncl= 2±1


Dark cosmology dk pela

Results

Best-fitting models give:

Vout= 160 km s-1

log(NHI/cm-2) = 20.23

Ncl= 2±1


Dark cosmology dk pela

Conclusion

• Fitting Lya lines requires information about several parameters.

A simple spectrum isn’t really enough.


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