Although they are cosmologically close at 750 light years apart (or 6x the black-hole sphere of influence), the supermassive dark holes located in UGC 4211 will not merge until a few hundred millions of years.
The artist’s concept shows the galaxy merging and two of its central black holes. Image credit: ALMA / ESO / NAOJ / NRAO / M. Weiss, NRAO, AUI & NSF.
UGC 4211 can be found in Cancer’s constellation, approximately 480,000,000 light-years from Earth.
The object, also known by the names LEDA 22660, MCG +02-20-013, or SWIFT J0804.6+1045 is an excellent candidate to study the final stages of galaxy mergings. These events occur less frequently in distant Universes and can make it difficult for observers.
In the new study, Eureka Scientific astronomer Michael Koss and his colleagues used the highly sensitive 1.3-mm receivers at the Atacama Large Millimeter/submillimeter Array (ALMA) to look deep into UGC 4211’s active galactic nuclei — compact, highly luminous areas in galaxies caused by the accretion of matter around central black holes.
The merger’s byproducts were devoured in two black holes. Surprisingly they were eating side-by-side, with only 750 light years between them.
Dr. Koss stated that simulations suggest most black hole binaries found in galaxies nearby would not be active because they’re more common than two black holes growing like ours.
ALMA’s use was revolutionary. The discovery of two black holes in the Universe so close to each other could open up new avenues for further research on this exciting phenomenon.
ALMA’s unique ability to see through huge columns of dust and gas, and attain very high spatial resolution allows it to view things close up.
Our study identified one of the nearest pairs of black holes within a galaxy merger. We also know galaxy mergers occur more frequently in distant Universes, so these black hole binaries may also be more frequent than we thought.
The study authors suggest that close-paired binary dark hole pairs could indeed be common, which may have significant implications for the future detections gravitational waves.
“It is possible that there might be many pairs supermassive black hole growing in galaxies’ centers,” stated Dr. Ezequiel, an astronomer from Universidad Catolica de Chile.
If this is true, we’ll be seeing frequent gravitational waves events due to the merging of these objects throughout the Universe in the future.”
Astronomers also analyzed data taken from NASA’s Chandra X-ray Observatory and NASA/ESA Hubble Space Telescope. ESO’s Very Large Telescope was used as well.
Dr. Treister stated, “Every wavelength tells an entirely different story.”
Hubble revealed the nuclei at high resolution, while ground-based optical imaging gave us the entire merging galaxy.
“X-ray observations showed that at least one galactic nucleus was active in this system,”
ALMA also showed us where these supermassive black hole growing and hungry were located.
All of this data has given us an even clearer view of why galaxies like ours are the way that they are and will be in the future.
“It is important that you see the same story with all the different images — there are two blackholes,” Dr. Chiara Mingarelli of Flatiron Institute, an Astronomer at the Center for Computational Astrophysics, said.
This is the same place where previous studies on supermassive black hole close-proximities have failed in the past.
It turned out there was only one black hole when people tried to follow them up.”
“This time, we have many observations. All in agreement.”
This study is published in Astrophysical Journal Letters.
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Michael J. Koss The authors and others. 2023. UGC 4211: Confirmed Dual Active Galactic Nuclear Nucleus at Local Universe 230 pc Nuclear Separation. ApJL 942, L24; doi: 10.3847/2041-8213/aca8f0