Data driven methods for the calibration of the energy scale of air Cherenkov telescopes

超过100 GeV的最高能量伽玛射线天文学领域是由地面成像空气切伦科夫望远镜（IACTs）推动的，它发现了许多天体粒子加速器，测量了银河系外的背景光，以及丰富的基础物理学计划，包括间接搜索暗物质，轴子样粒子和洛伦兹不不变违反。为了充分利用现有仪器以及计划中的切伦科夫望远镜阵列（CTA）的潜力，需要对仪器进行仔细校准。对于CTA，要求绝对能量校准的校准和稳定性优于10%。在拟议的项目中，我们将进一步发展我们以前的工作，即地面与空间伽玛射线望远镜的交叉校准。与我们之前的工作相反，更好的能量覆盖将允许使用能量重叠进行模型无关的交叉校准。我们提出了两种新的方法来校准模拟的能量刻度。DC方法将使用进入大气层的宇宙射线铁核产生的直接切伦科夫光。该方法将利用点扩散函数的高统计特性及其与模拟的比较：模拟和数据中能量尺度的转移导致模拟和数据的不匹配。反过来，这可以用来调整能量校准。这些方法相互补充，并与大气监测方法正交。由此产生的系统不确定性预计在绝对能量尺度上小于10%。

The field of gamma-ray astronomy at the highest energies beyond 100 GeV has been driven by ground based imaging air Cherenkov telescopes (IACTs) with the discovery of numerous celestial particle accelerators, measurement of extra-galactic background light as well as a rich programme of fundamental physics including indirect searches for Dark Matter, axion-like particles, and Lorentz invariance violation. In order to fully exploit the potential of current instruments as well as for the planned Cherenkov telescope array (CTA), a careful calibration of the instruments is required. For CTA, the calibration and stability of the absolute energy calibration is required to be better than 10%. In the proposed project, we will develop further our previous work on cross-calibrating ground based with space based gamma-ray telescopes. Contrary to our previous work, the better energy coverage will allow to do a model-independent cross calibration using the overlap in energy. We suggest two new approaches to calibrate the energy scale with simulations. The method DC will use the direct Cherenkov light generated by cosmic-ray iron nuclei entering the atmosphere. The method PSF will exploit the excellent characterization of the point spread function with high statistics and its comparison with simulations: a shift of the energy scale in simulations and data leads to a mismatch of simulation and data. In turn, this can be used to tune the energy calibration. The approaches are complementary with each other and orthogonal to atmospheric monitoring approaches. The resulting systematic uncertainties are expected to be smaller than 10% on the absolute energy scale.