Discovery of hard X-ray emission from Type II bursts of the Rapid   Burster
  We report on results of BeppoSAX Target Of Opportunity (TOO) observations of the source MXB 1730-335, also called the Rapid Burster (RB), made during its outburst of February-March 1998. We monitored the evolution of the spectral properties of the RB from the outburst decay to quiescence. During the first TOO, the X-ray light curve of the RB showed many Type II bursts and its broadband (1-100 keV) spectrum was acceptably fit with a two blackbody plus power law model. Moreover, to our knowledge, this is the first time that this source is detected beyond 30 keV. 
F. Frontera, N. Masetti, M. Orlandini, L. Amati, E. Palazzi, D. Dal   Fiume, S. Del Sordo, G. Cusumano, A.N. Parmar, G. Pare...