The three active black holes were found in galaxy J0148-4214 as it appeared about 1.2 billion years after the Big Bang. The finding strengthens the possibility that mergers accelerated the growth of black holes in the early universe.
three Black holes Massive black holes in a distant, ancient galaxy allow astronomers to examine how mergers helped black holes grow rapidly in the early universe.
Light from galaxy J0148-4214 has been traveling toward Earth for more than 12.5 billion years, revealing the system as it appeared just 1.2 billion years after the Big Bang. In this ancient galaxy, an international team has identified three massive black holes that are actively accreting matter, each pulling in material from a surrounding accretion disk.
At such a vast distance, the expansion of the universe stretches the galaxy's light toward longer wavelengths, creating a redshift of z=5.02, from which astronomers determined the distance of J0148-4214 and the period in cosmic history from which they were observing.
"This is the first evidence of the existence of three active black holes in one galaxy in the distant universe," says Dr. Hanna Obler, head of a research group at the Max Planck Institute for Extraterrestrial Physics and lead author of the study.
Two of the black holes are located near the center of the galaxy, and the projected distance between them is only 620 light-years. The third black hole is located in the outer region of the galaxy, about 5,500 light-years from the center.
According to Obler, the finding suggests that processes in the early universe were effective in bringing massive black holes closer together. These processes set the stage for massive black hole mergers, which researchers hope to detect in the future by looking forGravitational waves.
Observations on which theories of galaxy evolution are based indicate that in the early universe, galaxies often came close to each other and merged. The black holes at their centers could also have come close and merged, creating larger black holes at the centers of the resulting galaxies.
Hydrogen signatures revealed the black holes
Astronomers identified the black holes using unique spectral signatures produced by hydrogen atoms moving at very high speeds under the influence of their gravity. The spectrum obtained from the central region of the galaxy contained a complex pattern, the most likely explanation for which is the existence of two nearby black holes.
The pair could not be distinguished as separate point sources. So the researchers used spectroastrometry – a method that measures tiny spatial deviations in emission lines throughout the galaxy – to determine their location. A third active black hole was discovered in observations of the galaxy's outer region.
The team also considered alternative explanations for the spectral signatures, including supernovae, shock waves, stellar winds, and extremely massive stars. Analysis of additional spectral lines allowed the researchers to rule out these possibilities.
Different masses and surprising growth rates
The estimated masses of the three black holes are about 80 million, 600 thousand, and two million solar masses.
Despite its large mass, the black hole, which is about 80 million solar masses, is accreting matter at a slower rate than the black hole nearby, which is about 600 solar masses. The smaller black hole is accreting matter at such a high rate that it exceeds the maximum rate predicted by basic models of black hole growth – the Eddington limit.
"The data of James Webb Space Telescope "They allowed us not only to identify the three black holes, but also to estimate their masses, their accretion rates, and the mass of the stars in the galaxy," says Dr. Giovanni Mazulari, the second author of the study and a researcher at the Max Planck Institute.
According to him, the total mass of stars in the galaxy is estimated at about 1.3 billion solar masses, so black holes constitute a significant portion of the mass measured in it.
Two are expected to merge
The researchers estimate that the two black holes at the center of the galaxy will merge within a few hundred million years. According to Professor Roberto Maiolino of the University of Cambridge, who co-authored the study, the result strengthens the possibility thatmerging black holes There was another, faster route for their growth in the early universe.
The origin and future of the third black hole are still unclear. It may be a remnant of a previous merger and has been displaced from the center of the galaxy by gravitational recoil; another possibility is that it is now moving inward, towards the center of the galaxy.
The observations demonstrate the importance of integral field spectroscopy for detecting some active black holes in distant galaxies. Without the spatial information provided by the Webb Telescope's NIRSpec instrument, it is likely that only one of the three black holes would have been detected.
The system could be an early step in a process that will lead to the merger of massive black holes. Such mergers are expected to emit low-frequency gravitational waves that could be detected by space observatories such as LISA.
Questions and Answers
What was discovered in galaxy J0148-4214? Researchers have found evidence of three massive black holes actively accreting matter, two of which are near the center of the galaxy and the third is on its outskirts.
How were black holes identified? They were not imaged directly. The researchers detected the rapid movement of hydrogen gas around them using spatial spectroscopy on the James Webb Space Telescope's NIRSpec instrument.
Why is the finding important? The system strengthens the possibility that mergers between galaxies and their black holes helped black holes grow rapidly in the young universe.
Will the three black holes merge? The researchers estimate that the two central holes will merge within a few hundred million years. It is not yet clear whether the third hole is moving toward the center or was actually deflected away from it by a previous event.
Sources: Max Planck Institute for Extraterrestrial Physics; The scientific article in Astronomy & Astrophysics;
More on the subject on the science website
- Webb identifies candidate for 'star-like black hole' at cosmic dawn
- This is how black holes grew quickly to become supermassive in the early universe
- Webb Telescope Discovers Oldest Black Hole
- Dust may betray supermassive black holes kicked out of galaxy centers
- The European Space Agency is building a large antenna in space to listen for gravitational waves
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