1999A&A...349L..77P

We report the first simultaneous measurement of the broad band X-ray (0.3-150 keV) spectrum of the neutron star x-ray binary 4U 0614+091. Our data confirm the presence of a hard x-ray tail that can be modeled as thermal Comptonization of low-energy photons on electrons having a very high temperature, greater than 220keV, or as a non-thermal powerlaw. We detected a spectral feature that can be interpreted as reprocessing, via Compton reflection, of the direct emission by an optically-thick disk and found a correlation between the photon index of the power-law tail and the fraction of radiation reflected which is similar to the correlation found for black hole candidate x-ray binaries and Seyfert galaxies.