Broad-band X-ray observations of Cir X-1

Abstract

We present broad-band (2–88 keV) X-ray observations of the X-ray binary Cir X-1 with the TTM and HEXE instruments on board of the Mir space station. The observations were made in January/February 1989. The spectrum is best described by a model with 3 components: a blackbody at low energies, an iron line and a Comptonised hard continuum. The spectrum is variable during our observations; when the Comptonised component becomes harder, the spectrum becomes softer below 15 keV. The high-energy spectrum resembles that of X-ray binary pulsars.