SIMBAD references

We present an on-going BATSE/CGRO investigation devoted to search for hard X-ray emission from X-ray bursters with the earth occultation and occultation transform imaging techniques. This is a collaboration between the BATSE team at the NASA/Marshall Space Flight Center, Columbia University and the Harvard Smithsonian Center for Astrophysics. In this paper, we first outline the scientific objectives of our investigation and briefly overview some results obtained within our collaboration. We present preliminary results on two Galactic center X-ray bursters Terzan 2 and GX354-0 for which simultaneous SIGMA data exist and we report on the possible BATSE detection of a hard X-ray outburst from 4U 1705-44. Finally, we discuss on the hard X-ray emission from neutron stars and review the different criteria that have been proposed for distinguishing them from black hole systems on the basis of the properties of their hard X-ray emission.