Constraints on the Steady and Pulsed Very High Energy Gamma-ray Emission from Observation of Psr B1951+32 / Ctb 80 with the Magic Telescope

We report on very high energy γ-observations with the MAGIC Telescope of the pulsar PSR B1951+32 and its associated nebula, CTB 80. Our data constrain the cutoff energy of the pulsar to be less than 32GeV, assuming the pulsed γ-ray emission to be exponentially cut off. The upper limit on the flux of pulsed γ-ray emission above 75GeV is 4.3 · 10 photons cm sec, and the upper limit on the flux of steady emission above 140GeV is 1.5 ·10 photons cm sec. We discuss our results in the framework of recent model predictions and other studies. Subject headings: acceleration of particles — gamma rays: observations —pulsars: individual (PSR B1951+32) — radiation mechanisms: nonthermal a Universität Würzburg, D-97074 Würzburg, Germany b Institut de F́ısica d’Altes Energies, Edifici Cn., E-08193 Bellaterra (Barcelona), Spain c ETH Zurich, CH-8093 Switzerland d Universidad Complutense, E-28040 Madrid, Spain e Universitat Autònoma de Barcelona, E-08193 Bellaterra, Spain f Max-Planck-Institut für Physik, D-80805 München, Germany g Università di Padova and INFN, I-35131 Padova, Italy h Universität Dortmund, D-44227 Dortmund, Germany i University of Lódź, PL-90236 Lodz, Poland j Universitat de Barcelona, E-08028 Barcelona, Spain k Yerevan Physics Institute, AM-375036 Yerevan, Armenia l Tuorla Observatory, Turku University, FI-21500 Piikkiö, Finland m Instituto de Astrofisica de Canarias, E-38200, La Laguna, Tenerife, Spain n Università di Udine, and INFN Trieste, I-33100 Udine, Italy o Università di Siena, and INFN Pisa, I-53100 Siena, Italy p University of California, Davis, CA-95616-8677, USA q Humboldt-Universität zu Berlin, D-12489 Berlin, Germany r Institute for Nuclear Research and Nuclear Energy, BG-1784 Sofia, Bulgaria s Author to whom correspondence should be addressed; [email protected] t INAF/Osservatorio Astronomico and INFN Trieste, I-34131 Trieste, Italy u Università di Pisa, and INFN Pisa, I-56126 Pisa, Italy v ICREA and Institut de Cienciès de l’Espai, IEEC-CSIC, E08193 Bellaterra, Spain w ASIAA/National Tsing Hua University TIARA, PO Box 23141, Taipei, Taiwan, R. O. C.