HI Lyman-alpha equivalent widths of stellar populations
| Autor: | Maria A. Peña-Guerrero, Claus Leitherer |
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| Rok vydání: | 2013 |
| Předmět: |
Physics
Initial mass function Cosmology and Nongalactic Astrophysics (astro-ph.CO) Star formation FOS: Physical sciences Astronomy and Astrophysics Astrophysics Astrophysics::Cosmology and Extragalactic Astrophysics Galaxy Atmosphere Stars Astrophysics - Solar and Stellar Astrophysics Space and Planetary Science Astrophysics::Solar and Stellar Astrophysics Astrophysics::Earth and Planetary Astrophysics Absorption (electromagnetic radiation) Equivalent width Astrophysics::Galaxy Astrophysics Solar and Stellar Astrophysics (astro-ph.SR) Line (formation) Astrophysics - Cosmology and Nongalactic Astrophysics |
| DOI: | 10.48550/arxiv.1310.1155 |
| Popis: | We have compiled a library of stellar Lyman-alpha equivalent widths in O and B stars using the model atmosphere codes CMFGEN and TLUSTY, respectively. The equivalent widths range from about 0 to 30 \AA in absorption for early-O to mid-B stars. The purpose of this library is the prediction of the underlying stellar Lyman-alpha absorption in stellar populations of star-forming galaxies with nebular Lyman-alpha emission. We implemented the grid of individual equivalent widths into the Starburst99 population synthesis code to generate synthetic Lyman-alpha equivalent widths for representative star-formation histories. A starburst observed after 10 Myr will produce a stellar Lyman-alpha line with an equivalent width of $\sim$ -10$\pm$4 \AA in absorption for a Salpeter initial mass function. The lower value (deeper absorption) results for an instantaneous burst, and the higher value (shallower line) for continuous star formation. Depending on the escape fraction of nebular Lyman-alpha photons, the effect of stellar Lyman-alpha on the total profile ranges from negligible to dominant. If the nebular escape fraction is 10%, the stellar absorption and nebular emission equivalent widths become comparable for continuous star formation at ages of 10 to 20 Myr. Comment: Accepted for publication in The Astronomical Journal |
| Databáze: | OpenAIRE |
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