But this ULX has a shorter life than its predecessors. Within 10 days of NASA's observations with NuSTAR and Chandra telescopes, it went from undetectable to burning in light, then back to invisible just as quickly.
"Ten days is a really short time for such a bright object to appear," says Caltech researcher Hannah Earnshaw.
This could be a black hole or a neutron star
But black holes usually pick stars for much longer than 1
Neutron stars rotate so fast that its magnetic fields act as a barrier that stops debris from other astral objects that it attracts by striking the star and generating X-ray light. Only when a piece of material overcomes this barrier will the star emit bright X-rays like those in the photo.
"It would be like trying to jump on a carousel that spins at thousands of miles per hour," Earnshaw said.
This may explain the short observation period of ULX-4, NASA said. But if it does not shine again, its origin will probably remain an intergalactic mystery.