Observations of Very High Energy Gamma-Rays during Moonlight and Twilight with the MAGIC Telescope

摘要

We study the capability of the MAGIC telescope to observe under moderatemoonlight. TeV gamma-ray signals from the Crab nebula were detected with theMAGIC telescope during periods when the Moon was above the horizon and duringtwilight. This was accomplished by increasing the trigger discriminatorthresholds. No change is necessary in the high voltage settings since thecamera PMTs were especially designed to avoid high currents. We characterizethe telescope performance by studying the effect of the moonlight on thegamma-ray detection efficiency and sensitivity, as well as on the energythreshold.