{\em UIT\/}'s View of the Magellanic Clouds During Astro-2

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Session 20 -- Astro 2
Display presentation, Tuesday, June 13, 1995, 9:20am - 6:30pm

[20.11] {\em UIT\/}'s View of the Magellanic Clouds During Astro-2

J.Wm.Parker (Hughes STX, GSFC/LASP), T.P.Stecher (GSFC/LASP), The UIT Team

During the Astro-2 mission in March of this year, the Ultraviolet Imaging Telescope\/ obtained large-scale (40~arcmin diameter) images of many regions in the Large and Small Magellanic Clouds. We present far-UV (1300-1800~\AA) UIT\/ images of the observed fields, which include the regions 30 Doradus, Shapley Constellation III, N\,4, N\,11, N\,70, N\,79, NGC\,330, and NGC\,346 as well as regions containing field populations in the SMC and LMC bar. We present preliminary photometric results for some OB associations, and discuss how the UIT\/ observations will increase our knowledge of the populations of massive stars in the Magellanic Clouds. The OB associations in these regions are of particular interest considering the advantages of studying massive stars in the far-UV. These hot stars emit most of their flux in the UV (because of their high temperatures and also because of decreased line-blanketing due to the relatively low metallicity of the Clouds), so massive stars are strongly selected in the far-UV and the cooler, low-mass stars are suppressed. The proximity of the Clouds allowed us to achieve photometric completeness in the 30 Doradus region to far-UV magnitude of approximately 14.0~mag (or a mass of about 14~$\cal{M}_{\odot}$) for a 473.0~sec exposure during Astro-1; during Astro-2 we obtained exposure times in the Clouds up to three times longer. UV photometry of hundreds of stars allows us to study the unusual extinction curves and far-UV rise in the Clouds.

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