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| - Resonance line transfer in clumpy media
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| - Abstract. A three-dimensional radiative transfer code is used to calculate resonance line profiles and the fraction of escaping photons for a static clumpy medium which contains a continuous absorber. For the description of the clumpy configurations, a two-phase model is employed. We investigate models with line centre optical depths of τ≤ 100 which correspond to column densities of neutral hydrogen of N≤ 1016 cm−2 in the case of Lyα and a turbulent velocity of 100 km s−1. We find that the influence of a clumpy medium on the fraction of escaping photons mainly depends on the distribution of the source regions. If the photons are predominantly emitted in the clumps, the reduction of the total flux due to the continuous absorber is hardly affected or at most slightly enhanced for small filling factors. If the photons are emitted in the interclump matter or in a spatially confined central region, the flux reduction is weaker in comparison to the homogeneous case. For filling factors f≤ 0.01 the flux is essentially unchanged. The line profiles of the homogeneous models show the typical absorption feature in the centre of the line profile for models with τ > 1. For inhomogeneous models, these double-peaked line profiles gradually change to a Gaussian line profile with decreasing filling factor and increasing opacity of the continuous absorber. Peculiar line profiles, i.e. triple-peaked or single-peaked line profiles with broad shoulders or extended wings, appear for models with intermediate filling factor 0.1 < f< 0.4. They are superpositions of double-peaked line profiles and simple Gaussians. Global velocity fields destroy the symmetry and lead to multiple-peaked Lyα lines as observed in some high-redshift galaxies.
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