Black hole seen forming stars

A black hole at the centre of a nearby galaxy is helping stars to form, a new study has revealed...

Black holes are patches of space so gravitationally dense that not even light can escape. They are most often depicted as destructive monsters, swallowing everything in their paths. But new pictures taken with the Hubble Space Telescope show that the interactions between a black hole and its environment are more complex.

"Its not actually matter coming out directly from the black hole," explains Zachary Schutte, the lead author on the paper. "As gas and dust are falling onto the black hole, this environment is such high energy that some of the matter gets expelled away."

This expelled matter is forming two "outflows", ferocious jets of hot gas and dust travelling at hundreds of kilometres per second. The material is corkscrewing out from the black hole at the centre of the galaxy Henize 2-10 like water from a hosepipe held a foot from the end. The shockwaves from one of these outflows are buffetting clouds of nearby gas and dust, compressing the material and causing it to collapse into new stars.

According to Schutte, the hot gas flowing out from the black hole is slamming into patches of nearby cold matter forming a hydrodynamic shock, much like the waves you see at the bow of a ship traveling.  "This increases the density," continues Schutte, "which causes the stars to begin forming."  The stars are lighting up in super star clusters with masses a hundred thousand times the mass of our Sun.

Of particular interest to the researchers was the youth of the new star formation.  Estimates place the age of the stars being formed at around 5 million years. In astronomical terms, that is only a moment ago: our own Sun is a thousand times older.

This phenomenon has been seen before, but this example has shown that the interaction between a supermassive black hole and its host galaxy is complex, even down to the dwarf galaxy scale. Now that it has been shown to occur in smaller galaxies, and given the power of new telescopes being deployed, Schutte believes we will see more cases of this nurturing side of black holes.