Ultraviolet Emission from Strong X-Ray Sources as Observed with Iue

Abstract

In 1972, when the request for observing programs for the International Ultraviolet Explorer (IUE) was first made by NASA, ESA and the United Kingdom, a number of scientists recognized that observations in the ultraviolet of the strong galactic X-ray sources could be a fruitful activity. The underlying nature of those objects was understood. Their binary nature had been discovered through the X-ray observations which, combined with extensive optical observations and the insight gained through the tie to traditional ideas of stellar evolution, led to a picture whose general features are still accepted. The strong X-ray sources were taken to be close binary systems in which one object was a compact star, either a neutron star or a black hole, and the other object a common star in a stage of its life when it was undergoing great mass loss, either as a stellar wind or through Roche-lobe overflow.