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

TL;DR

This paper demonstrates that the MAGIC telescope can effectively observe very high energy gamma-rays during moonlight and twilight by adjusting trigger thresholds, expanding observational opportunities without hardware modifications.

Contribution

The study shows that MAGIC can operate under moonlight conditions by optimizing trigger thresholds, enabling more flexible gamma-ray observations without high voltage adjustments.

Findings

Gamma-ray signals from Crab nebula detected during moonlight and twilight

Telescope performance characterized under moonlight conditions

Observation capability extended without hardware modifications

Abstract

We study the capability of the MAGIC telescope to observe under moderate moonlight. TeV gamma-ray signals from the Crab nebula were detected with the MAGIC telescope during periods when the Moon was above the horizon and during twilight. This was accomplished by increasing the trigger discriminator thresholds. No change is necessary in the high voltage settings since the camera PMTs were especially designed to avoid high currents. We characterize the telescope performance by studying the effect of the moonlight on the gamma-ray detection efficiency and sensitivity, as well as on the energy threshold.