The major upgrade of the MAGIC telescopes, Part II: A performance study using observations of the Crab Nebula

TL;DR

This paper evaluates the performance improvements of the MAGIC telescopes after upgrades using Crab Nebula observations, highlighting enhanced sensitivity, resolution, and systematic uncertainty assessments.

Contribution

It provides a comprehensive performance study of the upgraded MAGIC telescopes, including sensitivity, resolution, and systematic uncertainties based on Crab Nebula data.

Findings

Sensitivity above 220 GeV is 0.66% of Crab flux in 50 hours.

Angular resolution is better than 0.07 degrees at relevant energies.

Systematic uncertainties are quantified as <15% in energy scale and 11-18% in flux normalization.

Abstract

MAGIC is a system of two Imaging Atmospheric Cherenkov Telescopes located in the Canary island of La Palma, Spain. During summer 2011 and 2012 it underwent a series of upgrades, involving the exchange of the MAGIC-I camera and its trigger system, as well as the upgrade of the readout system of both telescopes. We use observations of the Crab Nebula taken at low and medium zenith angles to assess the key performance parameters of the MAGIC stereo system. For low zenith angle observations, the standard trigger threshold of the MAGIC telescopes is ~50GeV. The integral sensitivity for point-like sources with Crab Nebula-like spectrum above 220GeV is (0.66+/-0.03)% of Crab Nebula flux in 50 h of observations. The angular resolution, defined as the sigma of a 2-dimensional Gaussian distribution, at those energies is < 0.07 degree, while the energy resolution is 16%. We also re-evaluate the effect of the systematic uncertainty on the data taken with the MAGIC telescopes after the upgrade. We estimate that the systematic uncertainties can be divided in the following components: < 15% in energy scale, 11-18% in flux normalization and +/-0.15 for the energy spectrum power-law slope.