标题： 由费米- LAT 揭示的 M16 区域内年轻星团 NGC 6611 的强子加速：对加速效率的限制 显示英文标题

标题： Hadronic acceleration in the young star cluster NGC 6611 inside the M16 region unveiled by Fermi-LAT: constraints on the acceleration efficiency

摘要： 上下文。年轻的巨大星团，长期以来被认为可能是银河宇宙射线的重要来源，最近被发现是伽马射线发射体，能量高达非常高的水平。 目标。为了量化这类源对银河宇宙射线池的贡献，我们需要估计这些系统的典型加速效率。 方法。我们搜索GeV波段的辐射，因为大部分能量是在这个波段发射的。 我们对费米-LAT在M16区域收集的数据进行分析，这是一个恒星形成区域，也被称为鹰状星云，其中包含年轻的巨大星团NGC 6611。 我们模拟恒星风终止激波处的加速以及通过风吹成的气泡的传播，以推导该过程的能量学并解释GeV观测结果。 结果。我们在与年轻巨大星团NGC 6611相关的分子云处发现了显著的GeV辐射。 我们将此解释为与在星团风终止激波处加速的粒子有关的强子辐射，并通过低密度风挖掘的气泡传播到云中。 我们的模型使我们能够对NGC 6611中的加速效率施加严格的限制，评估其在$\sim$1%和$\sim$4%之间。 显示英文摘要

摘要： Context. Young Massive Star Clusters, long considered as potentially important sources of galactic cosmic rays, have recently emerged as gamma-ray emitters up to very high energies. Aims. In order to quantify the contribution of this source class to the pool of Galactic CRs, we need to estimate the typical acceleration efficiency of these systems. Methods. We search for emission in the GeV band, as most of the energy is emitted in this band. We perform an analysis of Fermi-LAT data collected towards the M16 region, a star-forming region also known as the Eagle Nebula, which hosts the Young Massive Star Cluster NGC 6611. We model the acceleration at the stellar wind termination shock and the propagation through the wind-blown bubble to derive the energetics of the process and interpret the GeV observations. Results. We find significant GeV emission in correspondence of a molecular cloud associated to the Young Massive Star Cluster NGC 6611. We interpret this as hadronic emission associated to particle accelerated at the cluster wind termination shock and propagated through the low-density wind-excavated bubble to the cloud. Our modeling allows us to put firm constraints on the acceleration efficiency in NGC 6611, assessing it between $\sim$ 1 % and $\sim$ 4 %.