Hubble detects possible intermediate black hole hiding 6,000 light-years away
A rare intermediate-size black hole could be hiding a relatively close 6,000 light-years away within a globular star cluster.
Astronomers used the iconic Hubble Space Telescope to observe a compact region of space with the mass of 800 Suns that they believe to be a black hole.
According to a press statement, they believe they have found the "best evidence yet for the presence of a rare class of intermediate-sized black holes."
In search of an elusive black hole
Scientists have so far proven the existence of lower- and higher-mass black holes, but they have not so far been able to provide conclusive evidence for the existence of intermediate black holes.
Intermediate black holes are believed to be 10 to 10,000 times more massive than lower-mass stellar remnant black holes but not as large as supermassive black holes.
Now, the new Hubble observations suggest that the scientific community may have new evidence on its hands for the cosmic equivalent of the perenially-forgotten middle child.
Our galaxy contains millions of small black holes, and our universe is home to many supermassive black holes. But what about black holes "in between"?
— Hubble (@NASAHubble) May 23, 2023
Using Hubble, astronomers may have found evidence for an elusive intermediate-mass black hole: https://t.co/gTrXRFjcVJ pic.twitter.com/FiFLxnUv6s
The astronomers used Hubble to hone in on the central region of the globular star cluster Messier 4 (M4). "You can’t do this kind of science without Hubble," Eduardo Vitral of the Space Telescope Science Institute in Baltimore, Maryland, and lead author on a paper published in the Monthly Notices of the Royal Astronomical Society explained in the statement.
Detecting the black hole hiding in Messier 4
During their observations, Vitral and his team detected a possible intermediate-mass black hole with approximately 800 solar masses.
As with all black holes, the object can't be seen with the naked eye, but the researchers estimated its mass by studying the motion of surrounding stars caught in its gravitational field. The astronomers poured over 12 years' worth of Hubble observations of M4 before reporting their findings.
The team also drew from data collected by the European Space Agency's star-mapping Gaia spacecraft, which scanned over 6,000 stars belonging to M4.
Though the black hole is yet to be confirmed, the researchers explained that their models suggest such a compact region of high mass cannot be formed by any other known process.
"It's too tiny for us to be able to explain other than it being a single black hole," Vitral said in the statement. "Alternatively, there might be a stellar mechanism we simply don't know about, at least within current physics."