Si IV and C IV resonance lines as indicators of massive stars in starburst galaxies

Journal Article · Wed May 01 04:00:00 EDT 1991 · Astrophysical Journal; (United States)

DOI:https://doi.org/10.1086/170027· OSTI ID:5393913

Leitherer, C; Lamers, H J.G.L. ^[1]

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1. Space Telescope Science Institute, Baltimore, MD (USA) Wisconsin, University, Madison (USA) SRON, Utrecht (Netherlands)

The use of the ultraviolet lines of SI IV and C IV to study the initial mass function of massive stars in starburst galaxies is investigated. Radiatively driven wind models of stars with different metal content are computed. The resulting wind parameters are used as an input for line-profile calculations of Si IV and C IV. The metallicity dependence of the equivalent widths of these lines for representative hot star models is described. It is shown that the ratio of the Si IV and C IV line strengths decreases with decreasing metallicity under the conditions typically prevailing in stellar winds. It is also shown that in a combined spectrum of a galaxy, in which main-sequence stars dominate the UV spectrum, this ratio is expected to increase with decreasing metallicity for a constant initial mass function. The possible contribution of interstellar lines to the integrated spectrum is also discussed. It is found that spectral synthesis models do not allow one to derive parameters of the initial mass function as has been done previously. The mass-loss characteristics of massive stars directly affect the predicted line strengths, and they enter in an indirect way by modifying the evolutionary history of the stars. Both effects are not accounted for in synthesis models presently in existence. 58 refs.

• OSTI ID: 5393913
• Journal Information: Astrophysical Journal; (United States), Journal Name: Astrophysical Journal; (United States) Vol. 373; ISSN ASJOA; ISSN 0004-637X
• Country of Publication: United States
• Language: English

Related Subjects

640102* -- Astrophysics & Cosmology-- Stars & Quasi-Stellar
Radio & X-Ray Sources
71 CLASSICAL AND QUANTUM MECHANICS
GENERAL PHYSICS
ABUNDANCE
CARBON
CHEMICAL COMPOSITION
ELEMENT ABUNDANCE
ELEMENTS
GALAXIES
IDENTIFICATION SYSTEMS
INTERSTELLAR SPACE
MAIN SEQUENCE STARS
MASS
MASS TRANSFER
MATHEMATICAL MODELS
NONMETALS
SEMIMETALS
SILICON
SPACE
SPECTRA
STAR MODELS
STARS
STELLAR ACTIVITY
STELLAR WINDS
ULTRAVIOLET SPECTRA