Imaging air Cherenkov telescopes (IACTs) detect the Cherenkov light from extensive air showers (EAS) initiated by very high energy (VHE) gamma-rays impinging on the Earths atmosphere. Due to the overwhelming background from hadron induced EAS, the di
scrimination of the rare gamma-like events is vital. The influence of the geomagnetic field (GF) on the development of EAS can further complicate the imaging air Cherenkov technique. The amount and the angular distribution of Cherenkov light from EAS can be obtained by means of Monte Carlo (MC) simulations. Here we present the results from dedicated MC studies of GF effects on images from gamma-ray initiated EAS for the MAGIC telescope site, where the GF strength is ~40 micro Tesla. The results from the MC studies suggest that GF effects degrade not only measurements of very low energy gamma-rays below ~100 GeV but also those at TeV-energies.
Imaging Air Cherenkov Telescopes (IACTs) detect the Cherenkov light flashes of Extended Air Showers (EAS) triggered by very high energy (VHE) gamma-rays impinging on the Earths atmosphere. Due to the overwhelming background from hadron induced EAS, t
he discrimination of the rare gamma-like events is rather difficult, in particular at energies below 100 GeV. The influence of the Geomagnetic Field (GF) on the EAS development can further complicate this discrimination and, in addition, also systematically affect the gamma efficiency and energy resolution of an IACT. Here we present the results from dedicated Monte Carlo (MC) simulations for the MAGIC telescope site. Additionally we show that measurements of sub-TeV gamma-rays from the Crab nebula are affected even for a low GF strength of less than 33 micro Tesla.
