Coronal C+3 in the LMC: Evidence for a Hot Halo

Abstract

Observations of interstellar C IV toward six stars in the Large Magellanic Cloud are described. These data were obtained with the GHRS on HST and with IUE. They provide the first unambiguous evidence that C+3 exists in the Large Magellanic Cloud away from regions where it could have been produced locally, as the six stars are of spectral type later than 08, as well as away from hot early-type stars or active regions. Significant differences between the velocities of the C+3 absorption and those of Hα emission near the stars shows that these ions are not co-spatial, implying that the C+3 originates in the halo of the LMC. It is shown that photo-ionization is unlikely to be the sole source of the C+3 and that the LMC halo thus contains hot gas.