EURD observations of interstellar radiation

The hot interstellar medium (ISM) has far-reaching effect upon the structur e of galaxies. Although ISM heating processes are fairly well understood, a fter decades of study, the processes that cool the hot interstellar medium remain obscure. The EURD spectrograph was designed to measure the diffuse c osmic background from 350 to 1100 Angstrom in order to study the hot ISM an d the mechanisms by which it sheds its energy. We present the first analysi s of EURD observations of the cosmic background. These EURD observations ha ve proven to be far more sensitive than previous work; compared to previous results, we have improved the limits to the intensity of 450 to 900 Angstr om line emission from the ISM by one to two orders of magnitude. Our limit to OVI 1032 Angstrom / 1038 Angstrom doublet of 7900 ph s(-1) cm(-2) str(-1 ) is the lowest yet reported. The EURD limits to line emission are less int ense than predicted by a variety theoretical models of the local ISM.