About 7,800 light-years away – in our galactic neighborhood – is the globular cluster NGC 6397, practically a tuff of stars held together by gravity. That pile of stars was previously thought to have an intermediate-sized black hole in its center. But on further inspection, a team from the Institute of Astrophysics in Paris determined that the cluster actually houses a pod of smaller black holes, which hold things together in a more diffuse system.
Previous research has suggested that the core of the cluster could be populated with such a conglomeration of star-sized black holes, but this work goes a step further by measuring the mass and extent of those objects. The team’s research was published this week in the journal Astronomy and Astrophysics.
To identify the mystery at the center of the cluster, the researchers looked at how stars near its center moved using data from two space telescopes, the Hubble Space Telescope and the European Space Agency’s Gaia Observatory.
“We found very strong evidence for an invisible mass in the dense core of the globular group, but we were surprised to learn that this additional mass is not ‘point-like,'” Eduardo Vitral of the Paris Institute of Astrophysics said in a statement. NASA release. If a single black hole were responsible, the mysterious mass would be more densely concentrated. “Ours is the first study to provide both the mass and magnitude of what appears to be a collection of black holes in most of the center of a collapsed globular cluster.”
Intermediate black holes have long been considered a missing link in the evolution of black holes. Perhaps less in the public eye than supermassive black holes (whose existence is proven) or small primordial black holes (which remain theoretical), intermediate black holes, as their name suggests, would help astronomers understand how these develop. enigmatic structures.
“Our analysis indicated that the orbits of stars are almost random in the entire globular group, rather than systematically circular or very elongated,” explained Gary Mamon, also at the Institute of Astrophysics in Paris, in the same version. If the orbits of the stars were coordinated, they would suggest a massive object to govern. Instead, the stars seemed to be invested in their own ad hoc movements. Mamon and Vitral believe that this is because dense stellar debris, such as white dwarfs, neutron stars, and black holes – formed when stars reach the end of their life and collapse into themselves – have sunk. towards the center of the cluster, in a kind of three-dimensional Plinko. On the contrary, the lower-mass stars moved to the periphery of the cluster.
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“The authors have carried out a thorough analysis and the conclusions of this paper show an unexpected evolution in the search for [intermediate black holes] in globular clusters, “said Misty Bentz, an astrophysicist at Georgia State University who is not affiliated with the recent newspaper.” However, there are a lot of assumptions that are needed when conducting studies. this kind, and the results still leave room for the possibility of a [intermediate black hole] in this globular cluster.
The artistic illustrations of the globular cluster, presented in the video above, look like someone perforated space-time with a stellar-scale rifle. The precipices of immense gravitational force leave the group; the remains of dead stars keeping their siblings alive together in a gravitational network (or stiffening them, depending on your perspective). It is no surprise that this region contains so many white dwarfs, neutron stars and black holes; NGC 6397 is an extremely old cluster, the clock at 12.6 billion years old, it gives or takes half a billion, giving the stars plenty of time to complete their life cycles.
Bentz said the new study does not fully show that the cluster contains more small black holes than a larger one, “but if this is the case, then it makes the origin of supermassive black holes even more mysterious than they already are! That’s because, she explained, “we expect supermassive black holes to have grown from smaller seeds. But the result of this study would suggest that it is actually difficult to fuse a lot of small black holes into a globular cluster, because the globular cluster is old and yet the small black holes are still hanging individually, not joined together.
It is an interesting finding. Although it was predicted that there were black holes in 1916 by Albert Einstein, only two years ago, in April 2019, scientists captured a real image by one. Clearly, we have much to learn about these mysterious objects.