Approximately one hundred sources of very-high-energy (VHE) gamma rays are known in the Milky Way, detected with a combination of targeted observations and surveys. A survey of the entire Galactic Plane in the energy range from a few tens of GeV to a few hundred TeV has been proposed as a Key Science Project for the upcoming Cherenkov Telescope Array Observatory (CTAO). This article presents the status of the studies towards the Galactic Plane Survey (GPS). We build and make publicly available a sky model that combines data from recent observations of known gamma-ray emitters with state-of-the-art physically-driven models of synthetic populations of the three main classes of established Galactic VHE sources (pulsar wind nebulae, young and interacting supernova remnants, and compact binary systems), as well as of interstellar emission from cosmic-ray interactions in the Milky Way. We also perform an optimisation of the observation strategy (pointing pattern and scheduling) based on recent estimations of the instrument performance. We use the improved sky model and observation strategy to simulate GPS data corresponding to a total observation time of 1620 hours spread over ten years. Data are then analysed using the methods and software tools under development for real data. Under our model assumptions and for the realisation considered, we show that the GPS has the potential to increase the number of known Galactic VHE emitters by almost a factor of five. This corresponds to the detection of more than two hundred pulsar wind nebulae and a few tens of supernova remnants at average integral fluxes one order of magnitude lower than in the existing sample above 1 TeV, therefore opening the possibility to perform unprecedented population studies. The GPS also has the potential to provide new VHE detections of binary systems and pulsars, to confirm the existence of a hypothetical population of gamma-ray pulsars with an additional TeV emission component, and to detect bright sources capable of accelerating particles to PeV energies (PeVatrons). Furthermore, the GPS will constitute a pathfinder for deeper follow-up observations of these source classes. Finally, we show that we can extract from GPS data an estimate of the contribution to diffuse emission from unresolved sources, and that there are good prospects of detecting interstellar emission and statistically distinguishing different scenarios. Thus, a survey of the entire Galactic plane carried out from both hemispheres with CTAO will ensure a transformational advance in our knowledge of Galactic VHE source populations and interstellar emission.

中文翻译：

---

使用 Cherenkov 望远镜阵列对银河系平面进行调查的前景


在银河系中已知大约有 100 个超高能 （VHE） 伽马射线来源，这些来源是通过有针对性的观测和调查相结合来探测的。对整个银河系平面进行能量范围从几十 GeV 到几百 TeV 的调查已被提议作为即将到来的切伦科夫望远镜阵列天文台 （CTAO） 的关键科学项目。本文介绍了银河平面巡天 （GPS） 的研究状况。我们构建并公开提供了一个天空模型，该模型结合了最近对已知伽马射线发射器的观测数据与三类主要已建立的银河系 VHE 源（脉冲星风星云、年轻和相互作用的超新星残余物和紧凑的双星系统）的合成种群的最新物理驱动模型，以及银河系中宇宙射线相互作用的星际发射。我们还根据最近对仪器性能的估计对观测策略（指向模式和调度）进行优化。我们使用改进的天空模型和观测策略来模拟 GPS 数据，对应于 10 年内 1620 小时的总观测时间。然后使用正在开发的方法和软件工具对数据进行分析，以获得真实数据。根据我们的模型假设和所考虑的实现，我们表明 GPS 有可能将已知的银河 VHE 发射器的数量增加近五倍。这相当于探测到两百多个脉冲星风星云和几十个平均积分通量比现有样本低一个数量级的超新星残余物，这些样本的平均积分通量高于 1 TeV，因此为进行前所未有的群体研究提供了可能性。 GPS 还有可能提供双星系统和脉冲星的新 VHE 探测，以确认存在具有额外 TeV 发射分量的假设伽马射线脉冲星群，并探测能够将粒子加速到 PeV 能量的明亮源 （PeVatrons）。此外，GPS 将构成对这些源类进行更深入后续观测的探路者。最后，我们表明，我们可以从 GPS 数据中提取对未分辨源漫射贡献的估计值，并且检测星际发射和统计区分不同情景的前景很好。因此，使用 CTAO 从两个半球对整个银河系平面进行的调查将确保我们对银河 VHE 源种群和星际发射的了解取得变革性进展。