J/A+A/531/A12 Grid of Lya radiation transfer models (Schaerer+, 2011)
Grid of Lyα radiation transfer models for interpreting distant galaxies.
Schaerer D., Hayes M., Verhamme A., Teyssier R.
<Astron. Astrophys. 531, A12 (2011)>
=2011A&A...531A..12S 2011A&A...531A..12S
ADC_Keywords: Models ; Interstellar medium ; Ultraviolet
Keywords: galaxies: starburst - galaxies: ISM - galaxies: high-redshift -
ultraviolet: galaxies - radiative transfer
Abstract:
Lyα is a key diagnostic for numerous observations of distant
star-forming galaxies, but detailed radiation transfer models are
required for interpreting them. We provide an extensive grid of 3D
radiation transfer models that simulate the Lyα and UV continuum
radiation transfer in the interstellar medium of star-forming
galaxies. We have improved our Monte Carlo MCLya code and used it to
compute a grid of 6240 radiation transfer models for homogeneous
spherical shells containing HI and dust surrounding a central source.
The simulations cover a wide range of parameter space. We present the
detailed predictions from our models including in particular the
Lyα escape fraction fesc, the continuum attenuation, and
detailed Lyα line profiles. The Lyα escape fraction is
shown to depend strongly on dust content, but also on other parameters
(HI column density and radial velocity). The predicted line profiles
show a wide diversity of morphologies, ranging from broad absorption
lines to emission lines with complex features. The results from our
simulations are distributed in electronic format. Our models should be
of use for interpreting observations from distant galaxies, for
other simulations, and should also serve as an important basis for
comparison for future, more refined, radiation transfer models.
Description:
Derived quantities fesc (Lyα escape fraction), fesccont
(escape fraction of continuum radiation close to Lyα), and
Lyα equivalent width for a constant input spectrum (flat
continuum) as a function of the 4 model parameters vexp (expansion
velocity), NHI (HI column density), b (HI velocity dispersion), tau_a
(dust absorption optical depth). The derived quantities have been
computed for all 6240 models described by the model parameters
and for different FWHM values of the input Lyα line.
Note that the derived quantities are identical for cases of spherical
infall with the same absolute radial velocity (|vexp|).
File Summary:
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FileName Lrecl Records Explanations
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ReadMe 80 . This file
table2.dat 58 68596 Predicted Lyα and continuum escape
fraction for all radiation transfer models
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Byte-by-byte Description of file: table2.dat
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Bytes Format Units Label Explanations
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1- 6 F6.2 km/s b [10/160] HI velocity dispersion in the shell
8- 11 F4.2 --- tau.a [0/4] Dust absorption optical depth
13- 17 F5.2 [cm-2] log(NHI) [16/21.7] logarithm (dec.) of HI column density
19- 24 F6.2 km/s Vexp [0/700] Expansion velocity
26- 32 F7.2 km/s FWHM [50/1000] Full width at half maximum of input
Lyα emission line
34- 40 F7.5 --- Fesc [0/1] Lyα escape fraction
42- 48 F7.5 --- Fesc-c [0/1] UV continuum escape fraction close to
Lyα
50- 58 F9.5 0.1nm W(Lya) Lyα absorption equivalent width
predicted for a flat UV continuum
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(End) Daniel Schaerer [Geneva Obs., CH], Patricia Vannier [CDS] 05-May-2011