Emily Chan
The team included black holes in some of their simulations because prior evidence has suggested that black holes could be present in the central regions of globular clusters.
Their results demonstrated that a population of stellar-mass black holes within Palomar 5 could have led to the configuration of stars we see now.
Orbital interactions would have thrown the stars out of the cluster and into the long stream, but only if there were a significantly higher number of black holes than previously predicted.
The stars escaping the cluster would have changed the proportion of black holes, leading to a major increase.
“The number of black holes is roughly three times larger than expected from the number of stars in the cluster, and it means that more than 20 percent of the total cluster mass is made up of black holes,” Gieles said.
He added that the black holes all had a mass that was 20 times greater than the mass of the sun and that they formed in supernova explosions when the cluster was still young. The team’s simulations illustrated that the cluster will disappear in around a billion years.
Right before this will happen, whatever remains of the cluster will be made up of entirely black holes that orbit the galactic center. It is likely that other globular star clusters will eventually share the same fate.
Overall, the findings have revealed that globular clusters might be a good place to look for black holes. It is believed that a lot of black holes form in star clusters.
The study was published in Nature Astronomy.
