However, this ULX had a shorter life than its predecessors. Within 10 days of observations with NASA's NuSTAR and Chandra telescopes, it was no longer detectable, burning brightly and just as quickly becoming invisible again.
"Ten days is a really short time when such a bright object appears," said Hannah Earnshaw, Caltech researcher.
It could be a black hole or a neutron star.
But black holes usually nibble far longer than 1
Neutron stars spin so fast that they are magnetic Fields act as a barrier that prevents debris from other astral objects that attract them from hitting the star and producing X-rays. Only when a piece of material passes this barrier does the star emit bright X-rays, as shown.
"It would be like trying to jump on a merry-go-round spinning at a speed of thousands of miles per hour," Earnshaw said.
This may explain the short observation range of ULX-4, NASA said. But if it does not light up again, its origin is likely to remain an intergalactic puzzle.