Black holes are often thought to be a fairly destructive force in the universe -- but there's a lot more to them than meets the eye. Most galaxies, it seems, can't exist without them; and they also may play a role in the formation of stars and galaxies.
A new discovery by a team of researchers using the National Science Foundation's Very Large Array in New Mexico deals very much with the destructive side. Peering 1.1 billion light-years from Earth at an otherwise "boring" area of space called the Teacup Galaxy (J1430+1339) the team has discovered violent storm activity at its core -- demonstrating just how catastrophic black holes can be.
"It appears that a supermassive black hole is explosively heating and blasting around the gas in this galaxy and, as a result, is transforming it from an actively star-forming galaxy into one devoid of gas that can no longer form stars," said study lead author Chris Harrison from The Centre for Extragalactic Astronomy at Durham University in the UK.
The two most common types of galaxy that we have observed in the universe are spiral and elliptical. Spiral galaxies -- like our own Milky Way, and the nearby Andromeda -- make up around 60 percent of the galaxies we have seen, and are rich in gas and alive with activity and star formation.Ellipticals, on the other hand -- making up 10-15 percent of all galaxies -- have very little gas and very little star formation, ageing with a minimum of new growth.
These elliptical galaxies, researchers theorise, started out their lives as active star-forming galaxies -- after all, the stars had to come from somewhere -- yet at some point, star formation slowed almost to a halt. This, recent research suggests, could be due to the black holes in their hearts.
And perhaps those black holes are storming, if the Teacup Galaxy is any indication. It has been identified as having a supermassive black hole at its core actively consuming material and while it already has the appearance of an elliptical galaxy, observations have found gas surrounding the galaxy, indicating that it is only in the process of transitioning into an elliptical galaxy.
"For many years, we've seen direct evidence of this happening in galaxies that are extremely bright when viewed through radio telescopes. These, rare, radio-bright galaxies harbor powerful jets, launched at the black hole, that plow into the surrounding gas," Harrison said. "However, to understand how all of galaxies in our Universe formed, we needed to know if these same processes occur in less extreme galaxies that better represent the majority."
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