Astronomers could have detected rare class of medium-sized black hole

Video Credit: ESA/Gaia/DPAC, CC BY-SA 3.0 IGO

In a groundbreaking discovery, the European Space Agency's Gaia mission may have detected the first-ever medium-sized black hole. Astronomers have long speculated about the existence of intermediate-mass black holes, which fall between the stellar-mass remnants of massive stars (up to 100 times the mass of the Sun) and supermassive central anchors of large galaxies (billions of times the mass of the Sun), but conclusive evidence has remained elusive until now.

Gaia explored the Scorpius constellation and honed in on the ancient globular star cluster Messier 4. Amidst the vast array of celestial bodies, Gaia captured an intriguing mass- a massive dark blob at the heart of the cluster, about 800 times more massive than our Sun.

Have we detected the first medium-sized black hole?🤔 Our @ESAGaia spacecraft has captured a huge dark blob, 800 times more massive than our Sun which seems to be squeezed into a surprisingly small volume of space suggesting it could be an intermediate-mass black hole.🔗… pic.twitter.com/zrScyhRNLB

— ESA (@esa) May 23, 2023

According to the researchers, this dark mass at the centre of Messier 4 looks different - despite its tremendous size, the strange object appears to be compressed into an unexpectedly small volume of space.

"Using the latest Gaia and Hubble data, it was not possible to distinguish between a dark population of stellar remnants and a single larger point-like source. So one of the possible theories is that rather than being lots of separate small dark objects, this dark mass could be one medium-sized black hole," says Eduardo Vitral from the Space Telescope Science Institute, who led this research.

While the existence of intermediate-mass black holes remains tantalizingly uncertain, the Gaia mission's observation of the colossal dark blob in Messier 4 has ignited hope that we may be on the verge of a breakthrough.

The findings are published in Monthly Notices of the Royal Astronomical Society.