A black hole with extremely powerful jets has been found in the nearby galaxy Messier 83 (M83) by a team of Australian and American researchers, as we report in the journal Science today.
Black holes are by definition invisible, but when matter falls towards (and then into) them, they turn into a very efficient class of engines.
Chuck in some fuel (any kind of matter will do) and you get a huge amount of energy extracted from it as it falls into the gravitational field of the hole; eventually, the infalling gas crosses the horizon and is lost forever (or not) to our view.
If a car engine could be as energy efficient as a black hole, we could drive to Saturn and back with one litre of petrol (based on typical gasoline combustion efficiency of 45 MJ/kg, compared with the energy released by accretion onto a black hole, about 10 billion MJ/kg).
We don't have black-hole-powered cars because nobody knows how to make pocket-size black holes on Earth. But Nature has found ways of making black holes and using them as compact sources of energy. The most energetic or most explosive sources in the universe (such as quasars and gamma-ray bursts) are powered by the gravitational field of black holes, not by nuclear fusion which powers the sun and all other stars.
The more we explore the cosmos around us, the more evidence we find of active black holes and the effect they have on their surroundings. The newly-identified object in M83 (named MQ1, as the most energetic microquasar in M83) is the latest, striking example.
Measuring the jet power is more tricky. Jets eventually slam into the surrounding interstellar gas, shocking and heating it, so a black hole with powerful jets tends to be surrounded by an expanding, elongated "bubble" of hot ionised gas and free electrons. By measuring the size and luminosity (both the optical and radio emission) of this bubble, we estimate the power of the jets and for how long they have been switched on. This is precisely what we did for MQ1 in the M83 galaxy.
We inferred a huge jet power, a few million times higher than the total power of the sun, but similar to a few other black holes discovered in nearby galaxies over the past decade.
So, MQ1 is not a total oddity or an experimental glitch; but it is the only one in its class (so far) for which we can also constrain the mass of the black hole, via X-ray measurements of the radiation emitted by the infalling gas.