publication . Preprint . 1998

Massive star populations in I Zw 18: A probe of stellar evolution in the early universe

Schaerer, Daniel; de Mello, Duilia; Leitherer, Claus; Heldmann, Jennifer;
Open Access English
  • Published: 28 May 1998
Abstract
We present a study of the gaseous and stellar emission in I Zw18, the most metal-poor star-forming galaxy known. Archival HST WFPC2 and FOS data have been used to analyze the spatial distribution of [OIII], Halpha, and HeII 4686. The latter is used to identify Wolf-Rayet stars found by ground-based spectroscopy and to locate nebular HeII emission. Most of the HeII emission is associated with the NW stellar cluster, displaced from the surrounding shell-like [OIII] and Halpha emission. We found evidence for HeII sources compatible with 5-9 WNL stars and/or compact nebular HeII emission as well as residual diffuse emission. New evolutionary tracks and synthesis mod...
Subjects
arXiv: Astrophysics::Cosmology and Extragalactic AstrophysicsAstrophysics::Galaxy AstrophysicsAstrophysics::Solar and Stellar AstrophysicsAstrophysics::High Energy Astrophysical PhenomenaAstrophysics::Earth and Planetary Astrophysics
free text keywords: Astrophysics
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