Using archival data from the Gemini North telescope, a team of astronomers measured the pair supermassive black holes Heaviest ever found: 28 billion times the mass of the Sun.
Almost all massive galaxies host a supermassive black hole in its center. When two galaxies merge, their black holes They can form a binary pair, meaning they are in interlocking orbits.
These binaries are supposed to eventually merge, but this has never been observed. The question of whether such an event is possible has been debated among astronomers for decades. In a paper published in The Astrophysical Journal, a team of astronomers presented new insights into this question.
A single binary that can be seen separately
In a new study, a supermassive black hole a binary star located in the elliptical galaxy B2 0402. +379. This is a single binary system supermassive black hole it has never been resolved in sufficient detail to see the two objects separately, and it holds the record for the smallest distance ever directly measured: just 24 light-years.
While this close separation predicts a strong merger, subsequent studies have revealed that the pair has been stuck at this distance for more than three billion years, which begs the question; What is the support?
To better understand the dynamics of this system and its ongoing merger, the team examined archival data from Gemini North’s Gemini Multi-Object Spectrograph (GMOS), which allowed them to determine the velocities of nearby stars black holes.
“The excellent sensitivity of GMOS allowed us to map the increasing velocities of stars as we look closer to the center of the galaxy,” said Roger Romani, a professor of physics at Stanford University and co-author of the paper. “From this we were able to derive the total weight black holes who live there.”
28 billion times more than the Sun
The team estimates that the mass of the binary star is a whopping 28 billion times that of the Sun, qualifying the pair as Black hole heaviest binary star ever measured. This measurement not only provides valuable context for the formation of the binary system and the history of its host galaxy, but supports the theory that the mass Black hole the supermassive binary star plays a key role in stopping a potential merger.
Understanding how this binary formed can help predict if and when a merger will occur, and several clues point to the pair’s formation through multiple galaxy mergers. The first is that B2 0402+379 is a “fossil cluster”, meaning it is the result of the merger of stars and gas from an entire cluster of galaxies into a single massive galaxy.
Furthermore, the presence of two supermassive black holesalong with their large combined mass, suggests that they were the result of the merger of several smaller black holes from multiple galaxies.
After the galactic merger, supermassive black holes They will not collide head-on. Instead, they begin to pass each other as they settle into a confined orbit. With each step they take, energy is transferred from it black holes to the surrounding stars. As they lose energy, the pairs are drawn closer and closer until they are only light-years away, where gravitational radiation takes over and they merge.
This process has been directly observed in couples black holes stellar masses (the first recorded case was in 2015 via gravitational wave detection), but never in a binary of the supermassive variety.
With new knowledge of the system’s extremely large mass, the team concluded that it would take an exceptionally large number of stars to slow the binary’s orbit enough to get so close.
Swept up by stars and gas
In the process, black holes They seem to have ejected almost all the matter in their vicinity, leaving the galactic core devoid of stars and gas. With no additional material available to further slow the pair’s orbit, their fusion has stalled in the final phase.
“Normally, galaxies with pairs appear black holes the lighter ones have enough stars and mass to merge quickly,” Romani said. “Because this pair is so heavy, it took a lot of stars and gas. “But the binary swept away the central galaxy of such mass, leaving it stagnant and accessible for our study,” he added.
Whether the pair will overcome their impasse and eventually merge over a time horizon of millions of years, or continue forever in orbital limbo, remains to be determined. If they merge, the resulting gravitational waves would be a hundred million times stronger than those created by fusion black holes stellar masses.
It is possible that the pair could travel this final distance through another galaxy merger, which would introduce additional material, or possibly a third, into the system. Black hole, to slow down the pair’s path enough to merge. However, given that B2 0402+379 is a fossil cluster, another galactic merger is unlikely.
“We hope to do a follow-up survey of the core of B2 0402+379 to see how much gas is present,” says Tirth Surti, a Stanford graduate student and lead author of the paper. “That should give us more information on whether supermassive black holes “They may eventually merge or remain stuck as binaries,” he added. (With information from Europa Press)
