Joint observations from China’s Einstein Probe and the Large High Altitude Air Shower Observatory have revealed the longest known X-ray tail of a pulsar wind nebula: roughly 42 light-years, aligned with ultrahigh-energy gamma-ray emission near a pulsar 4,600 light-years away. The paper appeared September 21. Chinese Academy of Sciences report and paper link
X-rays and gamma rays appear consistent with the same population of high-energy electrons, giving astronomers evidence for a route as well as a source. The particles retain a preferred direction across tens of light-years instead of immediately diffusing uniformly. An ordered magnetic field or a collimated outflow could produce the channel; current observations do not distinguish them. That limitation makes the result better, not smaller: the visible trail turns a broad mystery about particle propagation into two mechanisms that further observation can test.