The pulse shape and spectrum of the millisecond pulsar PSR J0218 4232 in the energy band 1-10 keV observed with BeppoSAX

We present the results of a BeppoSAX observation of PSR J0218+4232 which, for the first time, provides detailed information on the pulsar’s temporal and spectral emission properties in the broad band 1– 10 keV. We detected X-ray pulses with a pulsed fraction of 73±12 %. The pulse profile is characterized by two peaks phase separated by ∆φ = 0.47 ± 0.05. The pulsed spectrum is best described by a power–law of photon index 0.61±0.32 with an unabsorbed (2–10 keV) X-ray flux of 4.1×10 ergcm s implying a luminosity of Lx = 1.3 × 10 32 Θ (d/5.7 kpc) ergs and an X-ray efficiency of Lx/Ė = 4.8 × 10 −4 Θ (d/5.7 kpc) where Θ is the solid anglespanned by the emission beam.