‘Starburst’ galaxies: New snapshots revealed of the early universe

‘Starburst’ galaxies pictured 10 billion years ago

Brief period of star formation is ‘snuffed out’ – possibly by black holes

Young, bright galaxies go on to be biggest galaxies in universe

By
Rob Waugh

Last updated at 12:29 PM on 25th January 2012

Astronomers have captured a glimpse of the early universe – accurate measurements of ‘starburst’ galaxies, young, bright-burning galaxies forming stars at an incredible rate.

The galaxies are 10 billion light years away, and due to the speed light takes to reach us, we see them as they were 10 billion years ago, in the early universe.

Chandra

This image shows these distant galaxies, found in a region of sky known as the Extended Chandra Deep Field South, in the constellation of Fornax. The galaxies are so distant that their light has taken around ten billion years to reach us, so we see them as they were about ten billion years ago

A starburst is the most intense form of star formation known to science – but the scientists now believe that the star formation only lasts for 100 million years, a moment in astronomical terms.

The galaxies pictured go on to form massive elliptical galaxies – the largest in the universe, say the universe of Durham scientists, who used data from two telescopes in Chile, the Atacama Pathfinder Experiment and the Very Large Telescope, among others.

It also seems likely that the starbursts are abruptly ‘snuffed out’ by powerful forces.

‘We know that massive elliptical
galaxies stopped producing stars rather suddenly a long time ago, and
are now passive.

‘And scientists are wondering what could possibly be
powerful enough to shut down an entire galaxy’s starburst,’ says Julie
Wardlow of Durham University,
UK, a member of the team.

The team’s results provide a possible
explanation: at that stage in the history of the cosmos, the starburst
galaxies are clustered round quasars, with a supermassive black hole at their heart.

Quasars are among the most energetic
objects in the Universe — galactic beacons that emit intense radiation,
powered by a supermassive black hole at their center.

Mosaic image of starburst galaxy, Messier 82 (M82) taken today: Scientists now think that this vigorous phase of star formation is brief

Mosaic image of starburst galaxy, Messier 82 (M82) taken today: Scientists now think that this vigorous phase of star formation is brief

The region scanned by the scientists, revealing star-forming galaxies in the early universe

The region scanned by the scientists, revealing star-forming galaxies in the early universe

There is mounting evidence to suggest
the intense starburst also powers the quasar by feeding enormous
quantities of material into the black hole

‘In short, the galaxies’ glory days
of intense star formation also doom them by feeding the giant black hole
at their center, which then rapidly blows away or destroys the
star-forming clouds,’ explains David Alexander (Durham University, UK), a
member of the team.

The measurements were made by measuring the masses of the dark matter around the galaxies, and using computer simulations to study how these halos grow over time, the astronomers found that these distant starburst galaxies from the early cosmos eventually become giant elliptical galaxies — the most massive galaxies in today’s Universe.

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