New king of galaxy find
A team of astronomers has discovered new kind of galaxies which, although extremely old – formed less than a billion years after the Big Bang – create stars more than a hundred times faster than our own Milky Way.
The team made this discovery by accident when investigating quasars, which are super-massive black holes that sit at the centre of enormous galaxies, accreting matter. They were trying to study star formation in the galaxies that host these quasars.
- Quasars are thought to form in regions of the universe where the large-scale density of matter is much higher than average. Those same conditions should also be conducive to galaxies forming new stars at a greatly increased rate.
- Whether or not the fast-growing galaxies we discovered are indeed precursors of the massive galaxies first seen a few years back will require more work to see how common they actually are, said Eduardo Banados from Carnegie Institution for Science in Washington, DC.
- The team also found what appears to be the earliest known example of two galaxies undergoing a merger, which is another major mechanism of galaxy growth.
- The new observations provide the first direct evidence that such mergers have been taking place even at the earliest stages of galaxy evolution, less than a billion years after the Big Bang.