Ultraviolet Imaging Telescope Observations of the Magellanic Clouds

• Published in: The Astronomical journal 1998-07, Vol.116 (1), p.180-208
• Main Authors: Parker, Joel Wm, Hill, Jesse K, Cornett, Robert H, Hollis, Joan, Zamkoff, Emily, Bohlin, Ralph C, O'Connell, Robert W, Neff, Susan G, Roberts, Morton S, Smith, Andrew M, Stecher, Theodore P
• Format: Article
• Language: English
• ISSN: 1538-3881; 0004-6256; 1538-3881
• DOI: 10.1086/300419

We present wide-field FUV images of the LMC and SMC. These data were obtained by the Ultraviolet Imaging Telescope (UIT) during the Astro-1 and Astro-2 missions; the images provide an extensive FUV mosaic of the SMC and contain numerous regions in the LMC, covering a wide range of stellar densities and current star formation activity. A total of 47 LMC/Lucke-Hodge and 37 SMC/Hodge OB associations are completely or partially included in the observed fields. We present a catalog of FUV magnitudes derived from point-spread function photometry for 37,333 stars in the LMC, with a completeness limit of mUV 15 mag and a detection limit of mUV 17.5. The average uncertainty in the photometry is 0.1 mag. We divide the catalog into field stars and stars that are in DEM regions. We analyze each of these two sets of stars independently, comparing the composite UV luminosity function of our data with UV magnitudes derived from stellar evolution and atmosphere models in order to derive the underlying stellar formation parameters. We find a most probable initial mass function slope for the LMC field stars of = -1.80 +/- 0.09. The statistical significance of this single slope for the LMC field stars is extremely high, though we also find some evidence for a field star IMF slope of about -1.4, roughly equal to the Salpeter slope. However, in the case of the stars in the DEM regions, we find three IMF slopes of roughly equal likelihood. (Author)