Astronomers are gemini north telescope measured a binary supermassive black hole located within the elliptical galaxy B2 0402+379.
Artist's impression of the supermassive black hole binary in elliptical galaxy B2 0402+379. Image credit: NOIRLab / NSF / AURA / J. daSilva / M. Zamani.
The pair of compact objects at the center of B2 0402+379 are the only supermassive black hole binaries ever resolved in enough detail that both objects can be seen separately.
It holds the record for the smallest distance ever directly measured – just 24 light years.
While this close separation portends a strong merger, further research reveals that the pair has been stuck at this distance for more than 3 billion years, raising questions. What is the holdup?
To better understand the dynamics of this system and its stalled merger, Stanford University professor Roger Romani and his colleagues turned to archival data from Gemini North. Gemini multi-object spectrometer (GMOS) This allowed them to determine the speed of stars near the black hole.
“The excellent sensitivity of GMOS allowed us to map the increasing velocity of stars as they approach the center of the galaxy. This allowed us to estimate the total mass of black holes present there.” Professor Romani said.
The authors estimate that the binary star's mass is a whopping 28 billion times that of the Sun, making the pair the most massive binary black hole ever measured.
This measurement not only provides valuable background on the formation of binary systems and the history of their host galaxies, but also confirms the long-held belief that the mass of supermassive binary black holes plays a key role in preventing potential mergers. This supports the theory.
“The data archive provided by the International Gemini Observatory holds a goldmine of untapped scientific discoveries,” said Dr. Martin Still, NSF program director for the International Gemini Observatory.
“Measuring the mass of this extreme supermassive binary black hole is an awe-inspiring example of the potential impact of new research exploring its rich archive.”
Understanding how this binary formed can help predict if and when it will merge. Also, some clues indicate that the pair formed through multiple galaxy mergers.
First, B2 0402+379 is a “fossil cluster,” meaning it is the result of an entire galaxy cluster's worth of stars and gas merging into a single giant galaxy.
Additionally, the presence of two supermassive black holes, coupled with their large combined mass, suggests that they resulted from the merger of multiple smaller black holes from multiple galaxies.
After galaxies merge, supermassive black holes do not collide head-on. Instead, they start slingshotting each other as they settle into a certain trajectory.
Each time a black hole passes, energy is transferred from it to the surrounding stars.
Losing their energy, the pair are dragged together, and gravitational radiation takes over, merging them just a few light years away.
This process has been observed directly in pairs of stellar-mass black holes, first documented by the detection of gravitational waves in 2015, but has never been observed in binaries of supermassive black holes.
With new knowledge about the system's extremely large mass, astronomers concluded that it would take a very large number of stars to slow down the binary enough to make its orbits so close together. .
In the process, the black hole seems to have blown away almost all the material around it, depleting the galaxy's center of stars and gas.
The merger of the two companies stalled in the final stages, as there was nothing left to further slow the companies' trajectory.
“Galaxies with lighter black hole pairs usually seem to have enough stars and mass to quickly merge the two,” Professor Romani said.
“The pair is so massive that we needed a lot of stars and gas to get the job done. But binaries scour the galaxy for such material, causing it to stagnate, making it impossible for our research to do so.” has been made accessible.”
It remains to be determined whether the pair will overcome stasis and eventually merge on a timescale of millions of years, or remain in orbit forever in limbo.
If they merged, the resulting gravitational waves would be 100 million times more powerful than those produced by the merger of stellar-mass black holes.
The pair could potentially conquer that final distance via another galactic merger. In that case, additional material, or potentially a third black hole, could be injected into the galaxy, slowing the pair's orbits enough for a merger.
However, given that B2 0402+379 is a fossil cluster, further galaxy mergers are unlikely.
“We're looking forward to tracking the core of B2 0402+379 to find out how much gas is present,” said Tirth Surti, an undergraduate at Stanford University.
“This should give us more insight into whether supermassive black holes may eventually merge or remain stuck as binaries.”
of result will appear in astrophysical journal.
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Tirth Surti other. 2024. Central kinematics and black hole mass of 4C+37.11. APJ 960, 110; doi: 10.3847/1538-4357/ad14fa
Source: www.sci.news
