A pulsar 4,600 light-years away is trailing an X-ray tail about 42 light-years long, roughly 250 trillion miles. It is the longest such tail ever found behind a pulsar.
The Einstein Probe satellite's telescope and the XMM-Newton satellite captured the tail behind PSR J1740+1000. Einstein Probe observed it for about 70,000 seconds, and XMM-Newton for more than six times as long. The tail lines up with very high-energy gamma rays that China's LHAASO observatory had recorded in that part of the sky.
What is happening there
A pulsar blows a wind of charged particles around itself. Electrons accelerated in that wind travel outward and emit X-rays along the way.
The same electrons collide with photons from their surroundings and hand them energy. The result is gamma radiation above one petaelectronvolt.
Why it matters
According to the paper, the particles do not spread out evenly right after leaving their source. They can travel in a preferred direction for tens of light-years.
That means the spot where radiation shows up may only mark the end of a long particle journey, not the place where the particles were born. A gamma-ray source offset from a pulsar is not necessarily a false match.
The paper comes from researchers at the Institute of High Energy Physics of the Chinese Academy of Sciences and Nanjing University, with a commentary by Gabriele Ponti's group at Italy's National Institute for Astrophysics.
