X-ray observations of SS433 by Ginga

Abstract

We observed SS433 with the X-ray astronomy satellite Ginga for five days, and detected a drop in X-ray intensity centered at the phase of the optical primary minimum. The intense broad line at E = 7 keV in the observed energy spectrum is considered to be the blue-shifted iron emission line from the jet. The intensity of the emission line changed almost proportionally to the continuum intensity at 5 – 10 keV during the eclipse. The spectral hardness also changed together with the intensity, which suggests that this is indeed an eclipse of a harder X-ray component near the base of the jet. The eclipse fraction of the line is ≅ 50%, indicating that the X-ray emission region of the jet is larger than the companion. Constraints on the mass of the compact object and the length of the X-ray emitting jet are derived from the geometrical analysis of the light curve.