Meet the galaxy builders
Do quasar's powered by super-massive black holes build galaxies?
Black holes have been a staple villain of science fiction for decades. They are portrayed as sinister behemoths that lurk in the dark recesses of the universe ready to devour anything unfortunate enough to fall within their grasp. This destructive reputation has taken a blow this week as a new study has revealed a black hole that is actually creating a new galaxy from scratch.
Supermassive black holes – up to hundreds of millions of times more massive than our Sun –have been known to exist at the heart of galaxies for some time. Even our home galaxy, the Milky Way, has a very large black hole lurking in its centre. Why nearly all galaxies contain a large black hole and why galaxies with a greater numbers of stars house larger black holes is one of the most debated subjects in modern physics.
Then, back in 2005, one was discovered that seemed break this ‘rule’ of star to black hole ratio and was effectively ‘naked’ – missing any kind of home galaxy at all. Revisiting the black hole in a new study – using data from Europe’s Very Large Telescope located in Chile – astronomers have revealed that, although there are no stars in this black hole’s immediate vicinity, it does have a relatively nearby ‘companion’ galaxy that is unusually rich in bright and very young stars.
The black hole being studied – called HE0450-2958, is a type of supermassive black hole called a quasar. Unlike the black holes that live in the centre of most galaxies which are starving, inactive objects that have no matter to devour, quasars are extremely active and suck up so much matter that they shine brighter than an entire galaxy of stars. All other known quasars sit at the centre of a ‘host’ galaxy that they suck up to fuel their extraordinary energy output. However, scientists have discovered that quasar HE0450-2958 is spewing highly-charged matter out in jets that actually seem to be feeding its companion galaxy and fuelling star formation at a rate of 350 a year.
It is thought that the quasar and the new galaxy will eventually collide and the black hole will then ‘clothe’ itself in the galaxy to become a more ‘conventional’ quasar. Eventually, it will run out of material close enough to suck up and will finally settle down for a more inactive old age like the many other black holes that sit at the heart their galaxies.
It seems not all black holes are ‘evil’ after all.