Astronomers spy one of the first-ever galaxies to form

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  Last updated January 11, 2018 at 10:44 am

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Astronomers have spotted a a galaxy almost as old as the Big Bang itself, using the Large Millimeter Telescope (LMT), located on the summit of a 4,500-metre extinct volcano in Mexico’s central state of Puebla.


The dusty star-forming galaxy was revealed with the help of strong gravitational lensing. It was formed only a billion years after the Big Bang. Credit: iStock/Pixelparticle


The galaxy, known as object G09 83808, seen as it was 12.8 billion years ago, is one of the oldest ever to have been observed and one of the earliest to form after the Big Bang.


“The Big Bang happened 13.7 billion years ago, and now we are seeing this galaxy from 12.8 billion years ago, so it was forming within the first billion years after the Big Bang,” astrophysicist Min Yun told reporters.


“Seeing an object within the first billion years is remarkable because the universe was fully ionised, that is, it was too hot and too uniform to form anything for the first 400 million years.


“So our best guess is that the first stars and galaxies and black holes all formed within the first half a billion to one billion years. This new object is very close to being one of the first galaxies ever to form.”


There is only one other, slightly older and more distant object like this known, Yun says.


The galaxy was first detected by astronomers using the Herschel space telescope, where astronomers passed the information on to the LMT.


The LMT is operated jointly by the University of Massachusetts Amherst and Mexico’s Instituto Nacional de Astrofísica, Óptica y Electrónica. It began operations in 2011 as a 32-meter millimetre-wavelength radio telescope before built out to its full 50-metre diameter.


When fully operational in a few months it will be the largest, most sensitive instrument of its kind.


But it had some help in this case from gravitational lensing, which magnifies light passing near massive objects as predicted by Einstein’s theory of general relativity.


Yum says a huge galaxy between Earth and object G09 83808 acted as a giant magnifying glass and made it look about 10 times brighter and closer than it really is.


The discovery was published in Nature Astronomy.




About the Author

Bill Condie
Bill is former Head of Publishing at the Royal Institution of Australia. Previously he was Publisher of the popular science magazine, Cosmos, based in Melbourne, Australia. Bill has been a journalist for more than 30 years and his work has been published in Cosmos magazine, The Guardian, The Observer, The Times, The Daily Telegraph and the London Evening Standard.