The brightest, furthest pulsar in the universe

[Jonathan Scott]

An interesting challenge for the theorists:
https://phys.org/news/2017-02-brightest-furthest-pulsar-universe.html
An Ultra-Luminous X-ray source (ULX) has been found (NGC 5907 X-1) which definitely seems to contain a pulsar, yet it appears to be far more powerful than other such sources which have been assumed to be powered by black holes.

The emission appears to be far greater than the Eddington limit (where radiation pressure would prevent further infalling material) but the discovery team are suggesting that complex magnetic fields near to the surface could somehow get round that (perhaps by sweeping material in against the radiation pressure).

 

[lippyka]

The challenge for theorists is to develop a model of the ULX which explains how the pulsar can produce such powerful X-ray emission without breaking the Eddington limit.