RESULTS OF GINGA ROSAT SIMULTANEOUS OBSERVATION OF THE X-RAY BURST-SOURCE-1735-444/

We present a detailed analysis of simultaneous Ginga and ROSAT observa tions of the X-ray burst source 1735-444, during which the source was in an unusually high luminosity state. The source shows the characteri stics of an atoll source in the high-intensity (banana state, with a g eneral correlation between intensity and spectral hardness. A blackbod y component contributes similar to 15%-20% of the total flux when the conventional two-component model is used to fit the spectra. We also o bserved a bright burst with radius expansion al this very high luminos ity. The burst spectrum could not be described by a simple blackbody m odel. We discuss possible explanations.