Sterile neutrinos with masses in the keV range are well-motivated extensions to the Standard Model that could explain the observed neutrino masses while also making up the dark matter (DM) of the universe. If sterile neutrinos are DM then they may slowly decay into active neutrinos and photons, giving rise to the possibility of their detection through narrow spectral features in astrophysical x-ray data sets. In this Letter, we perform the most sensitive search to date for this and other decaying DM scenarios across the mass range from 5 to 16 keV using archival XMM-Newton data. We reduce 547 Ms of data from both the MOS and PN instruments using observations taken across the full sky and then use this data to search for evidence of DM decay in the ambient halo of the Milky Way. We determine the instrumental and astrophysical baselines with data taken far away from the Galactic Center, and use Gaussian process modeling to capture additional continuum background contributions. No evidence is found for unassociated x-ray lines, leading us to produce the strongest constraints to date on decaying DM in this mass range.

中文翻译：

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用 XMM-NewtonBlank-Sky 观测深度搜索衰变暗物质

质量在 keV 范围内的不育中微子是标准模型的一个很好的扩展，它可以解释观察到的中微子质量，同时也构成了宇宙的暗物质 (DM)。如果惰性中微子是 DM，那么它们可能会慢慢衰变为活跃的中微子和光子，从而增加通过天体物理 X 射线数据集中的窄光谱特征对其进行检测的可能性。在这封信中，我们使用档案XMM-Newton对质量范围从 5 到 16 keV 的这种和其他衰减 DM 场景进行了迄今为止最敏感的搜索数据。我们使用在整个天空中进行的观测减少了来自 MOS 和 PN 仪器的 547 Ms 数据，然后使用这些数据来搜索银河系周围光晕中 DM 衰变的证据。我们使用远离银河中心的数据确定仪器和天体物理基线，并使用高斯过程建模来捕获额外的连续谱背景贡献。没有发现不相关的 X 射线线的证据，这导致我们对这个质量范围内的衰减 DM 产生迄今为止最强的限制。