“Mythical beast” spotted in distant universe
One of the first galaxies to form has been imaged in detail for the first time. Andrew Masterson reports.
The second oldest galaxy ever detected has been spotted by a telescope built on top of an extinct volcano in Mexico.
The star-forming galaxy is thought to have formed in the first billion years following the Big Bang, 13.7 billion years ago. Only one other slightly older, more distant galaxy has ever been recorded.
“These high redshift, very distant objects are a class of mythical beasts in astrophysics,” says astrophysicist Min Yun, co-author of a paper in the journal Nature Astronomy.
“We always knew there were some out there that are enormously large and bright, but they are invisible in visible light spectrum because they are so obscured by the thick dust clouds that surround their young stars.”
Yun adds that the galaxy – which was first seen, at very low resolution, by the Herschel space telescope – is likely one of the oldest structures in existence.
"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,” he explains.
“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.”
The galaxy was observed by the Large Millimetre Telescope (LMT), which sits atop an extinct volcano in Mexico’s Puebla State and is operated jointly by the Instituto Nacional de Astrofísica and the University of Massachusetts.
The telescope began operation in 2012, but will not reach full operation capacity until later this year. It has been designed to measure millimetre wavelengths and thus reveal structures at the most distant points of the universe and time.