With a powerful magnetic-field, with hi-speed ions measured in the millions of electron-volts...
...I'm not surprised that the jovian environment emits X-Rays.
Why they are pulsed in 45 minute intervals, though, I don't know, but it would be great to find out.
Comets are also known emitters of X-Rays. A pretty ubiquitous phenomena
in the cosmos.
Jacob.