How teenage galaxies feed themselves

   Mar 15, 7:05 pm

Washington, Mar 15 (ANI): Astronomers have known for quite some time that the earliest galaxies were considerably smaller than the impressive spiral and elliptical galaxies that now fill the Universe.

Over the lifetime of the cosmos galaxies have put on a great deal of weight but their food, and eating habits , are still mysterious.

A new survey of carefully selected galaxies has focussed on their teenage years - roughly the period from about 3 to 5 billion years after the Big Bang.

By employing the state-of-the-art instruments on ESO's Very Large Telescope an international team is unravelling what really happened.

In more than one hundred hours of observations the team has collected the biggest ever set of detailed observations of gas-rich galaxies at this early stage of their development.

"Two different ways of growing galaxies are competing: violent merging events when larger galaxies eat smaller ones, or a smoother and continuous flow of gas onto galaxies. Both can lead to lots of new stars being created," explained Thierry Contini (IRAP, Toulouse, France), who leads the work.

The new results point toward a big change in the cosmic evolution of galaxies, when the Universe was between 3 and 5 billion years old.

Smooth gas flow (eso1040) seems to have been a big factor in the building of galaxies in the very young Universe, whereas mergers became more important later.

"To understand how galaxies grew and evolved we need to look at them in the greatest possible detail. The SINFONI instrument on ESO's VLT is one of the most powerful tools in the world to dissect young and distant galaxies. It plays the same role that a microscope does for a biologist," said Thierry Contini.

Distant galaxies like the ones in the survey are just tiny faint blobs in the sky, but the high image quality from the VLT used with the SINFONI instrument means that the astronomers can make maps of how different parts of the galaxies are moving and what they are made of.

There were some surprises.

"For me, the biggest surprise was the discovery of many galaxies with no rotation of their gas. Such galaxies are not observed in the nearby Universe. None of the current theories predict these objects," said Benoit Epinat, another member of the team.

"We also didn't expect that so many of the young galaxies in the survey would have heavier elements concentrated in their outer parts - this is the exact opposite of what we see in galaxies today," added Contini. (ANI)

Galaxies probably settled 2b yrs earlier than previously believed Oct 31, 12:07 pm
Washington, Oct 31 (ANI): Scientists have dug deeper and discovered that galaxies actually settled in to their current forms some 2 billion years earlier than previously thought.
Full Story
Space tourism appears to be safe for civilians Oct 31, 11:35 am
Washington, Oct 31 (ANI): A new study has revealed that space tourism and brief trip of weightlessness appears to be safe for most of the ordinary citizens.
Full Story
Antarctic ozone hole remains stable for 2014 Oct 31, 11:06 am
Washington, Oct 31 (ANI): The scientists from NASA and the National Oceanic and Atmospheric Administration (NOAA) have recently reported that the Antarctic ozone hole reached its annual peak size on Sept. 11, 2014, which was almost similar to that in 2013.
Full Story
NASA's Cassini captures sunlight glinting off Titan's seas Oct 31, 10:27 am
Washington, Oct 31 (ANI): NASA's Cassini spacecraft has recently observed sunlight glinting off of Titan's north polar seas.
Full Story
Comments

LATEST STORIES
TOP VIDEO STORIES
PHOTO GALLERY