- Galaxy formed like a firecracker in just 100 million years at start of cosmic time
- The 'red and dead' galaxy had three times more stars than our Milky Way today
- This discovery sets a new record for the earliest massive red galaxy
Astronomers have discovered a massive, inactive galaxy from a time when the Universe was only 1.65 billion years old.
Within a short time period this massive galaxy formed all its stars through an extreme star-burst event, researchers found.
But it stopped forming stars only a billion years after the Big Seed, to become a quiescent or 'red and dead' galaxy – the first found to exist at this ancient epoch.
An international team of astronomers found the 'monster' galaxy which has 300 billion stars crammed into a region of space about the same size as the distance from the Sun to the nearby Orion Nebula.
Astronomers expect most galaxies from this epoch to be low-mass minnows, busily forming stars, but this galaxy, known as ZF-COSMOS-20115, stayed as an inactive super galaxy.
'This discovery sets a new record for the earliest massive red galaxy', said Professor Glazebrook, Director of Swinburne's Centre for Astrophysics and Supercomputing, who led the team.
'This huge galaxy formed like a firecracker in less than 100 million years, right at the start of cosmic history', he said.
'This fast life and death so early in the Universe is not predicted by our modern galaxy formation theories'.
Until recently, models suggested dead galaxies or 'red nuggets' such as this should only exist from around three billion years after the Big Bang.
'It quickly made a monstrous object, then just as suddenly it quenched and turned itself off. As to how it did this we can only speculate', said Dr. Glazebrook.
Astronomers used the W M Keck telescopes in Hawaii to find these galaxies.
They took deep spectra at near-infrared wavelengths to find the presence of old stars and a lack of active star formation.
'It is an incredibly rare find that poses a new challenge to galaxy evolution models to accommodate the existence of such galaxies much earlier in the Universe', said Dr. Glazebrook.
Astrophysicists are still debating just how galaxies stop forming stars.
This research builds on an earlier study that suggested such dead galaxies could exist based on finding dim red objects in extremely deep near-infrared images.
'We used the most powerful telescope in the world, but we still needed to stare at this galaxy for more than two nights to reveal its remarkable nature,' co-author Professor Vy Tran, from Texas A&M University said.
'By collecting enough light to measure this galaxy's spectrum, we decipher the cosmic narrative of what stars and elements are present in these galaxies and construct a timeline of when they formed their stars,' Dr. Tran said.
