Astronomers discover 11 runaway galaxies

Washington, April 24:

In a first, astronomers have spotted 11 runaway galaxies that have been flung out of their homes to wander the void of intergalactic space.


Till date, scientists knew of about two dozen runaway stars and found one runaway star cluster escaping its galaxy forever.

“These galaxies are facing a lonely future, exiled from the galaxy clusters they used to live in,” said astronomer Igor Chilingarian from the Harvard-Smithsonian Centre for Astrophysics.

An object is a runaway if it is moving faster than escape velocity which means it will depart its home never to return.

In the case of a runaway star, that speed is more than a million miles per hour.

A runaway galaxy has to race even faster, travelling at up to six million miles per hour.

Chilingarian and study co-author Ivan Zolotukhin from the Moscow State University initially set out to identify new members of a class of galaxies called compact ellipticals.

These tiny blobs of stars are bigger than star clusters but smaller than a typical galaxy, spanning only a few hundred light-years.

In comparison, the Milky Way is 100,000 light-years across.

Compact ellipticals also weigh 1,000 times less than a galaxy like our Milky Way.

Their search identified almost 200 previously unknown compact ellipticals.

Of those, 11 were completely isolated and found far from any large galaxy or galaxy cluster.

Not only were the new-found compact ellipticals isolated, but also they were moving faster than their brethren in clusters.

This discovery represents a prominent success of the Virtual Observatory – a project to make data from large astronomical surveys easily available to researchers.

So-called data mining can result in finds never anticipated when the original data was collected.

“We recognised we could use the power of the archives to potentially unearth something interesting and we did,” Chilingarian added in the paper that appeared in the journal Science. (IANS)

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