BeppoSAX observations of the three Gamma-ray pulsars PSR B0656+14, PSR B1055-52 and PSR B1706-44

We report the results of the observations of the three gamma -ray pulsars PSR B0656+14, PSR B1055-52 and PSR B1706-44 performed with BeppoSAX. We detected a pulsed emission only for PSR B1055-52: in the range 0.1-6.5 keV the pulse profile is sinusoidal and the statistical significance is 4.5 sigma . The pulsed fraction was estimated 0.64+/- 0.17. This pulsation was detected also at energies greater than 2.5 keV suggesting either a non-thermal origin or a quite high temperature region on the neutron star surface. Spectral analysis showed that only the X-ray spectrum of PSR B1706-44 can be fitted by a single power-law component, while that of PSR B1055-52 requires also a blackbody component (kT = 0.075 keV) and that of PSR B0656+14 two blackbody components (kT1 = 0.059, kT2 = 0.12 keV).