Just like a runner hitting the wall at the end of a race, supermassive black holes face a similar challenge as they approach each other, coming to a virtual standstill in the final parsec.
Recent research indicates that dark matter could be the key to overcoming this last obstacle.
This is because researchers have identified a crucial behavior of dark matter that has been previously overlooked – its ability to interact with itself.
“The assumption of dark matter particles interacting is an additional component not present in all dark matter models,” explained the co-authors of the study. Dr. Gonzalo Alonso Alvarez. “Our argument is that only a model with these features can address the final parsec problem.”
What is the final parsec problem?
The final parsec problem refers to the challenge that slows down the black holes before they merge.
This discovery follows a previous study that detected gravitational waves resulting from the merging of supermassive black holes, each a billion times the mass of the sun.
In the new study published in Physics Review Letter, researchers found that the black holes came to a halt at just one parsec away from each other.
The question remains: if black holes cannot merge, how are gravitational waves produced?
The answer may lie in a better understanding of dark matter behavior, which may facilitate the merger of supermassive black holes over the final parsec.
When two galaxies collide, their supermassive black holes begin to orbit each other. Gravity slows them down, bringing them close to merging before their orbits shrink too much to support the final collapse. Interaction with a halo of dark matter then absorbs the remaining orbital energy, allowing the black holes to eventually merge.
This new model is supported by the Pulsar Timing Array, which detects gravitational waves originating from supermassive black hole mergers predicted by Alonso Alvarez and his team.
“Our study offers a new perspective on understanding the nature of dark matter particles,” said Alonso-Alvarez. “Observations of supermassive black hole mergers can provide insights into these particles.”
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Source: www.sciencefocus.com
