A rare type of black hole whose existence has never been proven could be orbiting our galaxy right now, the Hubble telescope reveals

The Hubble Space Telescope may have found a rare “missing link” black hole hidden in Earth’s cosmic backyard. Located approximately 6,000 light-years away at the core of the nearby star cluster Messier 4, the intermediate-mass black hole candidate is an ultradense region of space with the mass of 800 Suns, causing nearby stars to orbit it as ” a swarm of bees.” a beehive,” according to the researchers who detected it.

“It’s too small for us to explain other than it being a single black hole,” said the study’s lead author. Eduardo Vitral, an astrophysicist at the Space Telescope Science Institute in Maryland, said in a statement. “Alternatively, there could be a stellar mechanism that we just don’t know about, at least within current physics.”

Black holes are born from the collapse of giant stars and grow by gorging themselves on gas, dust, stars and other black holes. Currently, known black holes tend to fall into two general categories: stellar-mass black holes, ranging from a few to a few dozen times the mass of the Sun, and supermassive black holes, cosmic monsters that can be as small as a few million. up to 50 billion times more massive than the sun.

Intermediate-mass black holes, which theoretically range from 100 to 100,000 times the mass of the Sun, are the most elusive black holes in the universe. while there have been several promising candidates, the existence of intermediate-mass black holes has not been definitively confirmed. This poses a puzzle for astronomers. If black holes grow from stellar to supermassive in size by gorging themselves in an endless feeding frenzy, the lack of confirmed sightings of black holes in their awkward adolescent phases points to an even bigger hole in our understanding of cosmic monsters.

To search for signs of a lurking intermediate-mass black hole, the authors of the new study pointed the Hubble Space Telescope toward the globular star cluster Messier 4. Globular clusters are groups of tens of thousands to millions of stars close together, many of which are which are among the oldest ever formed in our universe. Approximately 180 globular clusters dot our Milky Way galaxy and, because they have a high concentration of mass at their centers, they are ideal grounds for adolescent black holes.

Messier 4 is the closest globular star cluster to Earth. Using the Hubble and Gaia Space Telescopes, the researchers used 12 years of data to identify the stars in the cluster and study their motions around its center. By applying physical models of how these stars moved, the researchers found that the stars were moving around something massive and were not detectable directly in the center of the cluster. “We are very confident that we have a very small region with a lot of concentrated mass,” Vitral said. “It is about three times smaller than the densest dark mass we have found before in other globular clusters.”

The region the researchers found was more compact than they would expect if its intense gravity had been produced by other dense stellar bodies, such as neutron stars and white dwarfs, and would require 40 stellar-mass black holes clumped into a space of one-tenth as large. a light-year across to make the stars orbit them so intensely.

“The consequences are that they would merge and/or be kicked out in an interstellar pinball game,” the researchers wrote in the statement. To confirm that they detected an intermediate-mass black hole and didn’t accidentally discover some new physics, the researchers said more observations need to be made, possibly using the James Webb Space Telescope in conjunction with Hubble. “Science is rarely about discovering something new in a single moment. It’s about reaching a more certain conclusion step by step, and this could be a step to be sure that intermediate-mass black holes exist.” Timo Prusti, a project scientist at the Gaia telescope, said in the statement.

source: https://academic.oup.com/mnras/article/522/4/5740/7169309?login=false