X-ray data constrain dark matter decay Dark matter may consist of previously unknown forms of subatomic particles. An unidentified astronomical x-ray emission line has been interpreted as being caused by the decay of a dark matter particle. If this is correct, then dark matter in the halo of the Milky Way Galaxy should produce a faint emission line across the whole sky. Dessert et al. tested this hypothesis using observations by the XMM-Newton (X-ray Multi-Mirror Mission) space telescope. Analyzing blank-sky regions with a total exposure time of about a year, they found no evidence for the predicted line and set upper limits on the decay rate that rule out the previously proposed dark matter interpretation. Science, this issue p. 1465 X-ray observations of the Milky Way’s halo rule out proposed models of dark matter decay. Observations of nearby galaxies and galaxy clusters have reported an unexpected x-ray emission line around 3.5 kilo–electron volts (keV). Proposals to explain this line include decaying dark matter—in particular, that the decay of sterile neutrinos with a mass around 7 keV could match the available data. If this interpretation is correct, the 3.5-keV line should also be emitted by dark matter in the halo of the Milky Way. We used more than 30 megaseconds of XMM-Newton (X-ray Multi-Mirror Mission) blank-sky observations to test this hypothesis, finding no evidence of the 3.5-keV line emission from the Milky Way halo. We set an upper limit on the decay rate of dark matter in this mass range, which is inconsistent with the possibility that the 3.5-keV line originates from dark matter decay.

中文翻译：

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3.5 keV 线的暗物质解释与空白天空观测不一致

X 射线数据限制暗物质衰变 暗物质可能由以前未知形式的亚原子粒子组成。一条不明的天文 X 射线发射线被解释为由暗物质粒子衰变引起的。如果这是正确的，那么银河系光晕中的暗物质应该会在整个天空中产生一条微弱的发射线。甜点等。使用 XMM-牛顿（X 射线多镜任务）太空望远镜的观测结果验证了这一假设。分析总曝光时间约为一年的空白天空区域，他们没有发现预测线的证据，并设置了衰减率的上限，排除了先前提出的暗物质解释。科学，这个问题 p。1465 年对银河系晕的 X 射线观测排除了暗物质衰变的提议模型。对附近星系和星系团的观测报告了一条约 3.5 千电子伏 (keV) 的意外 X 射线发射线。解释这条线的提议包括衰变暗物质——特别是质量约为 7 keV 的无菌中微子的衰变可以与可用数据相匹配。如果这种解释是正确的，那么 3.5 keV 线也应该是由银河系光晕中的暗物质发射的。我们使用了超过 30 兆秒的 XMM-牛顿（X 射线多镜任务）空白天空观测来验证这一假设，但没有发现银河系晕产生 3.5 keV 线发射的证据。我们在这个质量范围内设置了暗物质衰变率的上限，这与 3.5 keV 线起源于暗物质衰变的可能性不一致。