This discovery, one of the only identified intermediate-mass black holes, lives in a similarly rare object known as a low-mass stripped nucleus.
Astronomers Black Hole Unlike others. With a mass of 100,000 suns, it is smaller than the black hole found in the center of the galaxy, but larger than the black hole created when a star explodes. This makes it one of the only confirmed intermediate mass black holes. This is an object that has long been sought after by astronomers.
“We detect very well the largest stellar black hole, which is 100 times larger than the Sun, and the supermassive black hole in the center of a galaxy, which is millions of times larger than the Sun. That’s not the case. The measurement of black between these. It’s a big gap, “said Anil Seth, an associate professor of astronomy at the University of Utah and a senior author of the study. “This discovery fills the gap.”
The Andromeda Galaxy, or M31, is our largest neighbor of the Milky Way Galaxy. Credit: NASA / JPL-Caltech
The black hole was hidden in B023-G078, a huge cluster of the nearest adjacent galaxy Andromeda. Researchers long thought to be globular clusters claim that B023-G078 is instead a stripped nucleus. The stripped nucleus was the wreckage of a small galaxy that fell into a large galaxy and gravity stripped the outer stars. All that remains is a small, dense nucleus that orbits a larger galaxy, with a black hole in the center of that nucleus.
“Previously, we found a large black hole in a huge stripped nucleus that was much larger than the B023-G078. Renucapeketti, lead author of the University of Liverpool John Moore, who began his research while in the United States, said: The clear case that one of these objects was finally found. “
The The research is Published on January 11, 2022. Astrophysical Journal..
The left panel shows a wide-field image of the M31 with a red box and an inset, showing the location and image of the B023-G78 where the black hole was found. Credits: Iván Éder, https: //www.astroeder.com/; HST ACS / HRC
Premonition for decades
B023-G078 was known as a giant globular cluster. This is a collection of spherical stars that are firmly connected by gravity. However, only one observation of the object that determines its total mass was about 6.2 million solar masses. For years, Seth felt it was something else.
“I knew that the B023-G078 object was one of Andromeda’s largest objects and thought it could be a candidate for a stripped nucleus, but I thought it could be. We needed data to prove. We’ve been applying it to various telescopes for years to get more observations, but my proposal has always failed, “says Seth. rice field. “When we discovered a supermassive black hole in a stripped nucleus in 2014, the Gemini Observatory gave us the opportunity to explore the idea.”
With new observation data from Gemini Observatory Hubble Space Telescope, Pechetti, Seth and their team calculated how mass is distributed within an object by modeling the object’s optical profile. Globular clusters have a characteristic light profile near the center that is the same shape as the outer region. B023-G078 is different. The central light is round and flattens outwards. The chemical composition of the star has also changed, with the central star containing more elements heavier than the elements near the edges of the object.
“Globular clusters are basically formed at the same time. In contrast, these stripped nuclei can repeat the formation episodes where gas falls into the center of the galaxy and forms stars. Star clusters can be dragged into the center by the gravity of the galaxy, “Seth said. “It’s like a dump for a lot of things. Therefore, stripped nuclear stars are more complicated than globular clusters, and that’s what we saw in B023-G078.”
Researchers used the mass distribution of the object to predict the speed at which the star would move anywhere in the cluster and compared it to the data. The fastest star was orbiting around the center. The central star was too late compared to their observations when they built a model without black holes. When they added a black hole, they got a speed that matched the data. Black holes add evidence that this object is a stripped core.
“The stellar velocities we are getting give us direct evidence that there is some sort of dark mass in the middle,” Peketti said. “It is very difficult for globular clusters to form large black holes, but if they are in stripped nuclei, there are already black holes left as the remains of small galaxies that have fallen into large galaxies. Must be. “
Researchers want to observe more stripped nuclei that may hold more intermediate-mass black holes. These are opportunities to learn about the population of black holes in the center of low-mass galaxies and how galaxies are constructed from smaller building blocks.
“We generally know that large galaxies are formed from the fusion of small galaxies, but these stripped nuclei allow us to decipher the details of their past interactions. I will do it, “said Seth.
See also: “100,000 detections M⊙ M31’s Largest Globular Cluster Black Hole: Tidally Striped Nucleus ”, Renuka Pechetti, Anil Seth, Sebastian Kamann, Nelson Caldwell, Jay Strader, Mark den Brok, Nora Luetzgendorf, Nadine Neumayer, Karina Voggel, January 11, 2022 Astrophysical Journal..
DOI: 10.3847 / 1538-4357 / ac339f
Other authors include Sebastian Kaman of Liverpool John Moore University. Nelson Coldwell, Harvard-Smithsonian Astrophysical Center; Jay Strader, Michigan State University; Mark den Brok, Leibniz-Institut für Astrophysik Potsdam; Nora Luetzgendorf, European Space Agency; Nadine Neumayer, Max Planck Institüt für Astronomie ..
