Probably a solar garden light that got flung into space and is rotating.
Space
Cover author: Michał Kałużny http://astrofotografia.pl/
GPM J1839–10 takes 22 minutes between pulses.
End Times starts playing
*breaks out the marshmallows*
The article makes no mention of the possibility of this being a binary system of some sort, although I would guess the physics involved for this type of burst are equally lacking in current models.
Because that doesn't fit.
The object sends X-ray pulses for 30-300 seconds every 22 minutes.
For a binary star system we would expect to see pulses while the neutron star is not behind the star and a short period without any pulses while the other star blocks it. Which is the inverse of the recorded pattern
In a tertiary or greater star system you could have longer periods where the star is blocked but the time between pulses would vary depending on the positions of other stars.
Personally I think it will end up being a pulsar that is slowing down and becoming a regular neutron star with something externally adding/removing mass from it causing it to speed up again.