Implications of the SPEAR FUV Maps on Our Understanding of the ISM
  The distribution of a low-density transition temperature (10^4.5 - 10^5.5 K)
gas in the interstellar medium conveys the character and evolution of diffuse
matter in the Galaxy. This difficult to observe component of the ISM emits
mainly in the far-ultraviolet (FUV) (912-1800 {\AA}) band. We describe spectral
maps of FUV emission lines from the highly ionized species CIV and OVI likely
to be the dominant cooling mechanisms of transition temperature gas in the ISM.
The maps were obtained using an orbital spectrometer, SPEAR, that was launched
in 2003 and has observed the FUV sky with a spectral resolution of \sim 550 and
an angular resolution of 10'. We compare distribution of flux in these maps
with three basic models of the distribution of transition temperature gas. We
find that the median distribution of CIV and OVI emission is consistent with
the spatial distribution and line ratios expected from a McKee-Ostriker (MO)
type model of evaporative interfaces. However, the intensities are a factor of
three higher than would be expected at the MO preferred parameters. Some high
intensity regions are clearly associated with supernova remnants and
superbubble structures. Others may indicate regions where gas is cooling
through the transition temperature.
