There's a Tiny, 60-Mile Black Hole Inside the Galaxy You Can See with Binoculars

The galaxy M83—often referred to as the Southern Pinwheel galaxy–is one of the most dramatic celestial objects in the Southern skies. Only 15 million light-years away, M83 is famous for being so close and luminous that it can be observed through binoculars. Now the ol' pinwheel has a new thing going for it: A microquasar named MQ1 powered by an extraordinary "fast and furious" black hole.

Microquasars form when stellar black holes find themselves a host star and establish a nice, comfy binary system with them. As they feed on the star's mass, they create an ultra-hot plasma disc and eject two jets of light energy from opposite directions (which makes them easy to spot and classify).

MQ1 was discovered during an ongoing, international effort to map M83, and it will become the first object of its kind to be studied in any significant detail. The mini-quasar is even weirder than a “regular” black hole, as if such a thing were possible. When scientists first observed the system, the assumption was that the black hole itself would be large, given its impressive influence on the surrounding area.

But despite being flanked by jets that blasted out over 20 light-years in either direction, the black hole itself turned out to be only 60 miles across. This is the first time a microquasar's diameter has been measured, so we don't know if such small dimensions are the norm for super-powerful systems. But the sake of comparison, the most energetic microquasar in our own galaxy is SS 433, and it's only a tenth as powerful as MQ1, further adding to the surprise over the latter's compact size.

An artist's interpretation of a microquasar. Photo: ESO/L. Calçada/M.Kornmesser

“The significance of the huge jet power measured for MQ1 goes beyond this particular galaxy,” Soria explained in a statement released by the International Centre for Radio Astronomy Research. “It helps astronomers understand and quantify the strong effect that black hole jets have on the surrounding gas, which gets heated and swept away.

“This must have been a significant factor in the early stages of galaxy evolution, 12 billion years ago, because we have evidence that powerful black holes like MQ1, which are rare today, were much more common at the time.”

This isn't the first time the bizarre properties of microquasars have astonished astronomers. In July 2010, Soria and his fellow ICRAR researchers discovered a microquasar in galaxy NGC 7793 with jets measuring an unprecedented 1,000 light-years across. This discovery was significant not just due to the size of the jets, but due to their content.

The jets were packed with X-ray radiation, but there turned out to be a higher-than-expected particle count too. According to the team, these particles triggered “a shockwave that causes heating and accelerates the expansion of the bubble,” explaining the microquasar's impressive reach.

The odd behavior of these objects has piqued the curiosity of radio astronomers worldwide. “By studying microquasars such as MQ1, we get a glimpse of how the early universe evolved, how fast quasars grew, and how much energy black holes provided to their environment,” said Soria.

We also get to marvel over the fact that a black hole that's about half as long as Long Island has an extended influence of 20 light-years. MQ1 may be a small fry, but it packs a serious cosmic punch.