The ripples that space-time creates when two things collide Black holesThese mysterious objects have taught us much.
These Gravitational wavesEncode information about black holes, including their masses, their inward-spiraling towards each other, spins, orientations, and their mass.
Scientists concluded that the majority of collisions occurred in this way. We’ve seen They have been in binary systems between black holes. They formed from a binary of huge stars, which then became black holes.
One of the more than 90 mergers we have seen so farOne stands out however as being very unusual. GW19052, which was detected in May 2019, emitted space-time ripples that were unlike any other.
“Its morphology, explosion-like structure and other observations are quite different than previous ones.” says astrophysicist Rossella GambaGerman University of Jena
She continues:“GW190521” was originally interpreted as the merger between two rapidly rotating black holes. However, its unique features led to us suggesting other interpretations.
The most notable is the short, sharp durationThe Gravitational waveIt was difficult to explain the signal.
Gravitational waves can be generated by the Actual mergerTwo black holes are like ripples created by a rock being dropped into a pond. These ripples are also caused by the binary interaction, which sends weaker ripples out as the two black holes get closer.
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“The shape and brevity – less than a tenth of a second – of the signal associated with the event lead us to hypothesize an instantaneous merger between two black holes, which occurred in the absence of a spiraling phase,” explains astronomer Alessandro NagarThe National Institution for Nuclear Physics of Italy.
There are several ways to make a pair black holes interact gravitationally.
The first is that they were together for some time. Perhaps even before the formations of baby stars from the same piece in space molecular clouds.
Another is when two objects move through space so closely that they are caught gravitationally in what’s known as a dynamical encounter.
Gamba and her colleagues believed that this was what happened with GW190521, so the created simulations to prove their hypothesis. To reproduce the strange, they mashed up black holes and adjusted parameters like spin, trajectory, mass, and mass. Gravitational waveIn 2019, signal detected
The results show that the black holes didn’t start in a binary, but they were caught in each others gravitational web. They stumbled past each other twice in an eccentric loop, before colliding to create one larger. Black hole. Neither of the black holes in this situation was spinning.
“We developed precise models by using both numerical simulations and state-of-the art analytical methods to explain the observation better than any other hypothesis.” says astronomer Matteo BreschiThe University of Jena
“The probability of error in this case is 1:4,300!”
The team claims that this scenario is more likely to occur in densely populated areas of space such as star clusters, where gravitational interactions are more common.
This is in line with other discoveries regarding GW190521. One of the black holes in this merger was Measured at 85 timesThe mass of Sun.
Our current models show that black holes larger than 65 solar masses cannot form from one star. This is the only way we know. Black holeThe mergers of two objects with lower mass can lead to the formation of this mass.
Gamba’s work with her colleagues revealed that the mass of the two black hole collisions was approximately 81 and 52 solarmasses. This is slightly lower than the previous estimates but still leaves one black hole outside of the single star core collapse pathway.
It’s still unclear if our models need tweaking, but hierarchical mergers – whereby larger structures form through the continuous merging of smaller objects – are Cluster environments are more likely to produce clusters of peopleWith a large number of dense objects.
It is considered extremely rare to have dynamic encounters between black holes. Gravitational waveThe data collected so far by LIGO, Virgo would support this. However, this doesn’t make it impossible. New work suggests that GW190521 might be the first detection.
A first sign that there may be more over the years. The Gravitational waveObservatories are being updated and maintained at the moment, but they will be online again in March 2023To observe a new run. KAGRA Japan will join LIGO’s detectors in America and Italy for an even stronger observing run.
It would be incredible to have more detections of GW190521.
The research was published in Astronomy in Nature.
