Very High-Energy Observations of PSR B1951+32

PSR B1951+32 is a γ-ray pulsar detected by the Energetic Gamma Ray Experiment Telescope (EGRET) and identified with the 39.5 ms radio pulsar in the supernova remnant CTB 80. The pulsar energy spectrum is consistent with an unbroken power law with differential photon index of -1.8 ± 0.1 between 50 MeV and 10 GeV. The EGRET data shows no evidence for a spectral turnover. Here we report on the first observations of PSR B1951+32 beyond 30 GeV. The observations were carried out with the 10 m γ-ray telescope at the Whipple Observatory on Mount Hopkins, Arizona. In 8.1 hours of observation we find no evidence for steady or periodic emission from PSR B1951+32 above ~260 GeV. Flux upper limits are derived and compared with model extrapolations from lower energies and the predictions of emission models.