The 12 UM Contribution of Nearby Galaxies to the Infrared Background.
Final rept. 1 Aug 89-30 Sep 94,
VIRGINIA UNIV CHARLOTTESVILLE DEPT OF ASTRONOMY
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There were twelve publications in the final with the emphasis on the study of blue compact galaxies. The blue compact dwarf galaxy He 2-10 has been observed in the mid-IR. The central regions contained two resolved components which have the same mid-IR properties but different H-alpha fluxes. The energy sources for the mid-IR to far-IR emission were studied and showed that the mid-IR emission unambiguously is associated with the young massive stars, but that the far-IR emissions requires the heating contribution from a slightly more evolved stellar population. The primordial helium abundance of low-metallicity blue compact galaxies was determined with high-quality spectrophotometric observations. The results were consistent with those obtained from chemical evolution models with differential galactic winds. The hot gas outflow in the blue compact dwarf galaxy VIIZw4O3 was observed. The X-ray morphology form ROSAT is interpreted as hot gas outflow from the core of the galaxy powered by the present starburst activity. The spatial distribution of blue compact galaxies is the Second Byurakan Survey were studied. The large deficiency of blue compact galaxies support the hypothesis that the majority of dwarf galaxies. High quality spectrophotometric observations of 15 supergiant HII regions in 14 new low-metallicity blue compact galaxies were made. It was concluded that all these heavy elements have a primary origin and were produced by the same massive stars. MM