The X-ray emission of SS 433.

Recent X-ray observations of SS 433 with the Ginga satellite, centered at the phases of optical primary minimum, revealed new information about the systems properties. The main observational result is that the spectrum of the source is extremely hard, best fitted with a thermal bremsstrahlung law with kT less than about 30 keV, which softens during eclipse to kT about 12 keV. The 6.7 keV iron line region appears to be very complex and varies with the precessional phase. It is argued that the X-ray flux from the jets is strongly modulated by large structures on the disk. If these can be modeled properly, they will provide important clues to the disk's physical properties which might lead to a better understanding of the precession mechanism.