This finding is one of the only confirmed intermediate-mass black holes that lives in an equally rare object called a low-mass, removed nucleus.

Astronomers discovered a Black hole Unlike the rest. At one hundred thousand solar masses, it is smaller than the black holes we find in the centers of galaxies, but larger than the black holes that are born when stars explode. It is one of the only definitive intermediate-mass black holes that astronomers have long sought.

“We have stellar black holes 100 times larger than our Sun and supermassive black holes at the centers of galaxies millions of times larger than our Sun, but they are not. Anil Seth, a senior author who co-authored the study, said: “This finding fills the gap.”

The black hole is hidden within B023-G078, a large galaxy in our nearest galaxy, Andromeda. Considered a globular cluster for a long time, researchers argue that B023-G078 is a decapitated nucleus. The severed nuclei are the remnants of small galaxies that have fallen large and their outer stars have been removed by gravity. What remains is a small, dense nucleus orbiting a large galaxy and a black hole in the center of that nucleus.

“Previously, we found larger black holes larger than B023-G078 inside massive, removed embryos. We know that low-mass removed embryos must have smaller black holes, but there is no direct evidence,” said Renuka Bechetti, lead author at John Moores University in Liverpool, in the U. Began research while present. “I think it’s beautiful. It’s clear that we have finally found one of these objects.

The The study was Released January 11, 2022 The Astrophysical Journal.

Decades of speculation

B023-G078 is known as a massive globular cluster – a spherical cluster of stars tightly bound by gravity. However, there was only one observation of the object that would determine its total mass, about 6.2 million solar masses. For years, Seth had a feeling it was something else.

“I knew B023-G078 was one of the biggest objects in Andromeda, and I thought it might be a candidate for a removed nucleus. But we needed data to prove it. We’ve been applying to different telescopes for many, many years to get more observations, and my proposals have always failed.” Said Seth. “When we discovered a huge black hole inside the removed fetus in 2014, the Gemini Laboratory gave us the opportunity to explore this idea.”

With their new tracking data and pictures from Gemini Labs Hubble Space Telescope, Bechetti, Seth and their team calculated how mass is distributed within an object by modeling the light profile of the object. A globular cluster has a signature light profile, which has the same shape as the outer regions near the center. B023-G078 is different. The light in the center is circular, then the plate moves outwards. The chemical composition of the stars also changes, with the stars in the center having heavier components than those near the edge of matter.

“Global galaxies are basically formed simultaneously. In contrast, these removed nuclei may have repetitive chapters, where gas falls to the center of the galaxy and forms stars. Other galaxies may be pulled to the center by the gravitational forces of the galaxy,” Seth said. “It’s a kind of place where a variety of objects accumulate, so stars in dissociated nuclei are more complex than globular clusters, which is what we saw in B023-G078.

The researchers used the mass distribution of the object to predict how fast the stars would move within the cluster and compare them with their data. High-speed stars were coming around the center. When they created a model without adding a black hole, the stars in the center were much slower compared to their observations. When they added the black hole, they gained a speed that matched the data. The black hole adds evidence that this material is a removed nucleus.

“The stellar velocities we receive provide direct evidence that there is some kind of dark mass at the center,” Bechetti said. “Spherical clusters are very difficult to form large black holes. But if it is in the removed nucleus, there must already be a black hole, which is the remnant of a small galaxy that fell into a large galaxy.

The researchers hope to observe more removed nuclei that may have larger intermediate mass black holes. These are an opportunity to learn more about the black hole population at the centers of low-mass galaxies and how galaxies are formed from smaller building blocks.

“We know that large galaxies usually form from the fusion of smaller galaxies, but these removed nuclei allow us to understand the details of those past interactions,” Seth said.

Note: “A 100,000 detection M_⁇ Renuka Bechetti, Anil Seth, Sebastian Kaman, Nelson Caldwell, Jay Strotter, Mark Tenbrook, Nora Louis Gendorf, Nadine Newmeyer, and Kareena Vogel 201 January 21, 2018 The Astrophysical Journal.
DOI: 10.3847 / 1538-4357 / ac339f

Other faculty include Sebastian Kaman of John Moores University in Liverpool; Nelson Caldwell, Harvard-Smithsonian Astronomical Center; Jay Strader, Michigan State University; Mark Denbrook, Leibniz Institute for Astrophysics Botstam; Nora Lutzgendorf, European Space Agency; Nadine Newmeyer, Max Planck Institute for Astronomy; And Karina Vogel, Observatory astronomer de Strasbourg.