A serendipitous gravitational lens

Nov 21, 2011
An optical image of "The Elliot Arc," a remote galaxy seen here as a purplish arc because of the distorting effect of a gravitational lens - the intervening foreground cluster of galaxies (seen here as white circles). Credit: Buckley-Geer et al.

(PhysOrg.com) -- The path traveled by a light beam will bend in the presence of matter. This remarkable prediction, reached by Einstein in his theory of general relativity, was confirmed by observations of the solar eclipse of 1919. One consequence of this phenomenon is that light from a distant galaxy passing by an intervening galaxy en route to earth will be distorted, much in the way that light passing through a glass lens will be bent, sometimes deforming the appearance of objects seen through it.

Astronomers call an intervening galaxy in this role a "gravitational lens"; the object whose light is bend is called the lensed galaxy. The first such gravitationally lensed object was discovered in 1979, and since then several dozen lensed galaxies have been found. Such discoveries are difficult to make, however, because the lensed galaxies are far away, very faint, and randomly found across the sky, while there are many millions of other galaxies that, at least at first glance, appear similar.

CfA astronomer Mark Brodwin is one member of a team of scientists examining a set of images taken by a sensitive optical survey of the extragalactic sky designed to study the cosmological . They discovered in one image a beautiful example of a gravitational lens in the form of a purplish ring around a galaxy. The lead author named the source "The Elliot Arc" after her nephew. Followup research found that the lensing galaxy is at a nominal distance of 4.9 billion light-years; studies of the Elliot Arc revealed that it is the distorted image of a much older and distant galaxy, located about 10.1 billion light-years away.

The scientists were further able to conclude that the closer galaxy is actually a gigantic with a combined mass of about 20,000 Milky Way galaxies. They also found that the appears to have much weaker star formation going on than is expected from current models - but then discoveries like this one, that push the limits of knowledge, often refine our understanding of the distant universe.

Explore further: Comet Jacques makes a 'questionable' appearance

Related Stories

Lensed galaxies

Nov 12, 2010

In 1915, Einstein amazed the world by predicting that the path of light could be bent by mass. As a consequence, light from a distant galaxy passing by an intervening galaxy en route to earth will be distorted. ...

Astronomers discover an unusual cosmic lens

Jul 16, 2010

Astronomers at the California Institute of Technology (Caltech) and Ecole Polytechnique Fédérale de Lausanne (EPFL) in Switzerland have discovered the first known case of a distant galaxy being ...

A magnified supernova

Sep 27, 2011

Supernovae are among astronomers most important tools for exploring the history of the universe. Their frequency allows us to examine how active star formation was, how heavy elements have developed, and the ...

'Big baby' galaxy found in newborn Universe

Sep 28, 2005

The NASA/ESA Hubble Space Telescope and NASA’s Spitzer Space Telescope have teamed up to 'weigh' the stars in distant galaxies. One of these galaxies is not only one of the most distant ever seen, but it appears to be unusually ...

Recommended for you

Comet Jacques makes a 'questionable' appearance

20 hours ago

What an awesome photo! Italian amateur astronomer Rolando Ligustri nailed it earlier today using a remote telescope in New Mexico and wide-field 4-inch (106 mm) refractor. Currently the brightest comet in ...

Image: Our flocculent neighbour, the spiral galaxy M33

20 hours ago

The spiral galaxy M33, also known as the Triangulum Galaxy, is one of our closest cosmic neighbours, just three million light-years away. Home to some forty billion stars, it is the third largest in the ...

Image: Chandra's view of the Tycho Supernova remnant

Jul 25, 2014

More than four centuries after Danish astronomer Tycho Brahe first observed the supernova that bears his name, the supernova remnant it created is now a bright source of X-rays. The supersonic expansion of ...

User comments : 3

Adjust slider to filter visible comments by rank

Display comments: newest first

antialias_physorg
not rated yet Nov 21, 2011
deleted - wrong thread
El_Nose
not rated yet Nov 21, 2011
this is not news
BillFox
5 / 5 (1) Nov 21, 2011
Inb4 neutron repulsion.