Towards a full Atmospheric Calibration system for the Cherenkov Telescope Array

TL;DR

This paper discusses developing a comprehensive atmospheric calibration system for the Cherenkov Telescope Array, emphasizing the integration of Raman LIDARs with other remote sensing tools to improve gamma-ray data accuracy.

Contribution

It proposes a multifaceted atmospheric calibration approach combining Raman LIDARs and additional instruments to enhance atmospheric monitoring for CTA.

Findings

Raman LIDARs are optimal for altitude-resolved atmospheric extinction measurement.

Synergy with radiometers, photometers, and other sensors improves calibration accuracy.

A comprehensive system can extend observation duty cycle and data precision.

Abstract

The current generation of Cherenkov telescopes is mainly limited in their gamma-ray energy and flux reconstruction by uncertainties in the determination of atmospheric parameters. The Cherenkov Telescope Array (CTA) aims to provide high-precision data extending the duty cycle as much as possible. To reach this goal, it is necessary to continuously and precisely monitor the atmosphere by means of remote-sensing devices, which are able to provide altitude-resolved and wavelength-dependent extinction factors, sensitive up to the tropopause and higher. Raman LIDARs are currently the best suited technology to achieve this goal with one single instrument. However, the synergy with other instruments like radiometers, solar and stellar photometers, all-sky cameras, and possibly radio-sondes is desirable in order to provide more precise and accurate results, and allows for weather forecasts and now-casts. In this contribution, we will discuss the need and features of such multifaceted atmospheric calibration systems.