MAGIC very large zenith angle observations of the Crab Nebula up to 100 TeV

Understand

Aims: We aim to measure the Crab Nebula gamma-ray spectral energy distribution in the ~100 TeV energy domain and test the validity of existing leptonic emission models at these high energies.

• Methods: We use the novel very large zenith angle observations with the MAGIC telescope system to increase the collection area above 10 TeV.
• We also develop an auxiliary procedure of monitoring atmospheric transmission in order to assure proper calibration of the accumulated data.
• This employs recording of optical images of the stellar field next to the source position, which provides a better than 10% accuracy for the transmission measurements.