Continuum Processes in BL Lacertae Objects

The X-ray emission from many BL Lac objects is not a smooth extension of the IR-UV synchrotron emission, but is caused by another process. Two competing theories for the origin of this X-ray emission is the familiar synchrotron-self-Compton model and the recent pair cascade model. A critical test of both models can be made by obtaining a series of observations of BL Lac that include UV observations in conjunction with data from the millimeter to the X-ray waveband. This experiment was not possible before the launch of GINGA, and the special properties of BL Lac make it uniquely suited for this program.