1994A&A...288..472B

We report the first hard X-ray/soft gamma-ray observations of the recently discovered bright binary millisecond pulsar PSR J0437-4715. The observations were performed with the French coded-mask imaging telescope SIGMA aboard the Russian GRANAT spacecraft. More than 30 hours of useful time were accumulated during two observations performed on May 17th, 1993 and May 21st, 1993. No high energy emission was detected neither in the individual sessions nor in their sum. The 2 σ upper limits derived in the 40 to 200 keV range correspond to a photon flux of 2.1x10^–3photons/cm²/s or equivalently to a luminosity of ≃7x10³²erg/s for a distance of 150pc, indicating that the magnetospheric efficiency of the conversion of the pulsar spin down power into hard X-rays is less than 7.0x10^–2 for PSR J0437-4715.