The discovery, one of the only confirmed medium-mass black holes, lives in an equally rare object known as a low-mass nucleus.
Astronomers discovered a
“>black hole Unmatched. With a hundred thousand solar masses, it’s smaller than the black holes we’ve found at the center of galaxies, but bigger than the black holes that are born when stars explode. This makes it one of the only confirmed medium-mass black holes, and an object astronomers have long sought.
«Nous avons de très bonnes détections des plus grands trous noirs de masse stellaire jusqu’à 100 fois la taille de notre soleil, et des trous noirs supermassifs au center de galaxies qui sont des millions de fois la taille de notre soleil n mais ‘There is no. All black measurements are in between these. “It’s a huge contradiction,” said lead author Anil Seth, associate professor of astronomy at the University of Utah and co-author of the study. “This discovery fills the void.”
Andromeda Galaxy, or M31, is the largest neighboring galaxy of the Milky Way. Credit: NASA/JPL-Caltech
The black hole was hidden in B023-G078, a massive star cluster in our nearest neighboring galaxy, Andromeda. Researchers have long believed it to be a globular star cluster, and researchers say B023-G078 is more than an abstract core. Trunk cores are the remnants of small galaxies that have fallen into larger galaxies and whose outer stars have been stripped away by gravitational forces. What remains is a small, dense nucleus orbiting the larger galaxy, and in the center of that nucleus is a black hole.
“Previously, we have found supermassive black holes in bare massive nuclei much larger than B023-G078. “We knew there must be smaller black holes in lower-mass abstract nuclei, but there was absolutely no direct evidence,” said lead author Renuka Bechti of Liverpool John Moores University, who started the research at the university. An obvious case that we finally found one of these things.
the study was Posted on January 11, 2022 in Astrophysical Journal.
The left panel shows a wide field image of M31 with the red square and inset showing the location and image of B023-G78 where the black hole was found. Credit: Evan Eder, https://www.astroeder.com/; HST ACS / HRC
Intuition for several decades
B023-G078 is known as a massive globular star cluster – a globular group of stars strongly bound together by gravity. However, there was only one view of the object that determined its total mass, about 6.2 million solar masses. For years, Seth felt it was something else.
“I knew object B023-G078 was one of the massive objects in Andromeda and thought it might be a candidate for an abstract nucleus. But we needed data to prove it. We’ve applied it to different telescopes for more observations of many, many years ago, and my proposals always failed,” Seth said. And when we discovered a supermassive black hole in a bare core in 2014, the Gemini Observatory told us it gave us the opportunity to explore the idea.
With their new observational data from the Gemini Observatory and images from
“>Hubble Space TelescopePechetti, Seth and their team calculated the body’s mass distribution by modeling its light profile. The spherical cluster has a characteristic optical profile of the same shape near the center as in the outer regions. B023-G078 is different. The light in the center is round and then becomes flat as it moves outward. The chemical composition of stars also changes, with the stars having more heavy elements in the center than those near the edge of the body.
“Global star clusters are essentially forming at the same time. By contrast, these bare cores can contain repeating formation rings, in which gas falls into the galactic center and forms stars. And other star clusters can be pulled toward the center by gravitational forces, Seth said: “It’s a waste land for a bunch of different things, so stars in bare cores will be more complex than they are in globular clusters and that’s what we saw in B023-G078.”
The researchers used the body’s mass distribution to predict how fast the stars should move in a particular location in the cluster and compared it to their data. The fastest stars revolve around the center. When they built a model without including a black hole, the stars in the center were very slow compared to their observations. When they added the black hole, they got speeds matching the data. The black hole adds to the evidence that this object is an abstract nucleus.
“The stellar velocities we’re getting give us direct evidence that there’s some kind of black mass in the middle,” Pichetti said. “It is very difficult for globular clusters to form large black holes. But if it is in a bare core, then there must already be a black hole, left as remnants of a smaller galaxy that fell into the larger one.
The researchers hope to spot more bare cores that may contain intermediate-mass black holes. This is an opportunity to learn more about the number of black holes at the center of low-mass galaxies and to learn how galaxies are built from smaller building blocks.
“We know that large galaxies usually form from merging smaller galaxies, but these bare cores allow us to decipher the details of these earlier interactions,” Seth said.
Reference: “Detected 100,000 M⊙ A black hole in the most massive globular cluster of M31: a tidal-abstracted core” by Renuka Bechti, Anil Seth, Sebastian Kaman, Nelson Caldwell, Jay Strader, Mark Dunn Brooke, Nora Lutzgendorf, Nadine Neumayer, and Karina Vogel, January 11, 2022 , Astrophysical Journal.
DOI: 10.3847 / 1538-4357 / ac339f
Other authors include Sebastian Kaman of Liverpool John Moores University. Nelson Caldwell, Harvard-Smithsonian Center for Astrophysics; Jay Strader, Michigan State University; Mark Den Bruck, Leibniz Institute for Astrophysics, Potsdam; Nora Lutzgendorf, European Space Agency; Nadine Neumayer, Max Planck Institute for Astronomy; and Karina Vogel, Strasbourg Astronomical Observatory.