We analyze archival Chandra X-ray Observatory observations of Jupiter to search for emission from the Galilean moons. X-ray emission has previously been reported from Io and Europa using a subset of these data. We confirm this detection, and marginally detect X-ray emission from both Ganymede and Callisto as well. The X-ray spectrum of Europa is strongly peaked around the neutral oxygen fluorescence line (525 eV), while Io’s has peaks at both oxygen and sulfur (2308 eV) plus a broad continuum between 350 and 5000 eV. Ganymede’s spectrum is similar to Io’s, but without the sulfur peak. A few events, mostly clustered around the oxygen line, are detected from Callisto. Using measurements by the Galileo mission of the specific intensity of ambient protons and electrons, we model the X-ray spectra and flux of the moons from two processes: particle-induced X-ray emission (PIXE) from the impact of energetic protons and X-ray emission from electron bremsstrahlung. With uncertainties of ...

中文翻译：

---

木星伽利略卫星的X射线发射：确定其表面成分和粒子环境的工具

我们分析木星的档案钱德拉X射线天文台观测资料，以寻找伽利略卫星的发射。先前已经使用这些数据的一部分从Io和Europa报道了X射线发射。我们确认了这种检测，并少量检测了木卫三和木卫四的X射线发射。欧罗巴的X射线光谱在中性氧荧光线（525 eV）附近出现强烈峰值，而Io在氧和硫（2308 eV）处均具有峰值，并且在350至5000 eV之间具有宽广的连续峰。木卫三的光谱与Io相似，但没有硫峰。从卡利斯托（Callisto）检测到一些事件，其中大部分都聚集在氧气管线周围。通过伽利略任务对周围质子和电子的特定强度的测量，我们通过两个过程对卫星的X射线光谱和通量建模：高能质子和电子致辐射的X射线发射引起的粒子诱导的X射线发射（PIXE）。具有...的不确定性