P-Cygni Type Lya from Starburst Galaxies

Sang-Hyeon Ahn; Hee-Won Lee; Hyung Mok Lee

doi:10.1046/j.1365-8711.2003.06353.x

paper

P-Cygni Type Lya from Starburst Galaxies

arXiv:astro-ph/0204004 · doi:10.1046/j.1365-8711.2003.06353.x

Abstract

P-Cygni type Lya profiles exhibited in nearly half of starburst galaxies, both nearby and high-z, are believed to be formed by an expanding supershell surrounding a star-forming region. We apply the Monte Carlo code which was developed previously for static and plane-parallel medium to calculate the Lya line transfer in a supershell of neutral hydrogen which are expanding radially in a spherical bulk flow. We consider typical cases that the supershell has the Lya line-centre optical depth of $τ_{0} = 1 0^{5} - 1 0^{7}$ , a radial expansion velocity of $V_{e} x p = 300 k m / s, an d t h e t u r b u l e n ceo f b = 40 k m / s . W e f in d t ha tt h er e a pp e a r a f e w e mi ss i o n p e ak s a tt h e f r e q u e n c i escor r es p o n d in g t o (2 N - 1) V_{e} x p, w h er e t h eor d er o f ba c k sc a tt er in g s N > 1. A s V_{e} x p - > b, t h ee m er g e n tp r o f i l es b eco m es imi l a r t o t h ose f or t h es t a t i c m e d i u man d t h e p e ak s a r e l ess p r o min e n t . W e a l so in v es t i g a t e t h ee f f ec t so f co l u mn d e n s i t y o f t h es u p er s h e l l o n t h ee m er g e n t L y a p r o f i l es . W e f in d t ha tt h e n u mb er an d t h e f l ux r a t i oso f e mi ss i o n p e ak s a r e d e t er min e d b y in t er pl a y o f$ τ_0$ and V_exp of the supershell. We discuss the effects of dust extinction and the implication of our works in relation to recent spectroscopic observations of starburst galaxies.

15 pages, 6 figures, submitted to MNRAS

P-Cygni Type Lya from Starburst Galaxies

Abstract

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