X-ray observations of high-excitation emission-line galaxies with the HEAO 1 scanning modulation collimator

We present data from the scanning modulation collimator on HEAO 1 which firmly establish high-excitation emission-line galaxies as a class of X-ray sources. For NGC 5506 and M82, the X-ray emission (1--13 keV) is shown to originate in the nulcear region of the galaxy; NGC 2992 and NGC 526a are also identified as X-ray emitters, but are not resolved. The latter is a new identification for 2A 0120--353, previously associated with the NGC 526/527 group. In these four particular cases, the observed X-ray emitting galaxies have a close companion, and the X-ray emission may have been triggered by a close encounter.