Studies towards an understanding of global array pointing for the Cherenkov Telescope Array

TL;DR

This paper presents initial simulation-based studies on the global array pointing accuracy of the Cherenkov Telescope Array, aiming to achieve a 3 arcsecond source localization precision at energies above 100 GeV.

Contribution

It introduces a toy Monte Carlo simulation framework to evaluate CTA's source localization accuracy under various mis-orientation scenarios and observing conditions.

Findings

Provides lower limits for CTA source localization accuracy.

Demonstrates the impact of telescope mis-orientation on pointing precision.

Framework can incorporate effects like atmospheric refraction and clouds.

Abstract

For the proposed Cherenkov Telescope Array (CTA), a post-calibration point-source location accuracy of 3 seconds of arc is aimed for under favorable observing conditions and for gamma-ray energies exceeding 100 GeV. In this contribution, results of first studies on the location accuracy are presented. These studies are based on a toy Monte Carlo simulation of a typical CTA-South array layout, taking into account the expected trigger rates of the different CTA telescope types and the gamma-ray spectrum of the simulated source. With this simulation code it is possible to study the location accuracy as a function of arbitrary telescope mis-orientations and for typical observing patterns on the sky. Results are presented for various scenarios, including one for which all individual telescopes are randomly mis-oriented within their specified limits. The study provides solid lower limits for the expected source location accuracy of CTA, and can be easily extended to include various other important effects like atmospheric refraction or partial cloud coverage.