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Astronomers at UMass Amherst and in Mexico, using the Large Millimeter Telescope located on the summit of a 15,000-foot extinct volcano in Mexico’s central state of Puebla, have detected the second most distant dusty, star-forming galaxy ever found in the universe, born witin the first one billion years after the Big Bang. It is the oldest object ever detected by the LMT. Credit UMass Amherst
Using a powerful new telescope, a team of astronomers has discovered one of the first massive galaxies to form about 12.8 billion years ago.
A team from the University of Massachusetts at Amherst and Mexico’s National Institute of Astrophysics, Optics and Electronics used the Large Millimeter Telescope (LMT) to detect the second most distant dusty, star-forming galaxy ever found in the universe.
“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, from UMass Amherst, said in a statement. “Seeing an object within the first billion years is remarkable because the universe was fully ionized, 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,” he added. “This new object is very close to being one of the first galaxies ever to form.”
The new object was first detected by astronomers using the Herschel space telescope, which only took very blurry pictures that yielded very little information of such distant objects.
Yun explained that the astronomers are able to tell that the object is very distant by measuring its redshift—a measurement of the universe’s expansion speed—as objects that are more distant have a larger redshift.
To measure the redshift, the researchers used a spectral line of atoms of molecules, each of which had a recognizable, discrete signature or fingerprint.
LMT is located on the summit of a 15,000-foot extinct volcano in Mexico’s central state of Puebla.
The telescope began collecting light in 2011 as a 32-meter millimeter-wavelength radio telescope and has since expanded to its full 50-meter diameter.
When it becomes fully operation it will be the largest, most sensitive single-aperture instrument of its kind in the world.
“This result is not a surprise, because this is what the LMT was built to do, but we are very excited,” he said. “These high redshift, very distant objects are a class of mythical beasts in astrophysics.
“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 added. “Paradoxically, the most prolific star-forming galaxies and thus the most luminous are also the most difficult to study using traditional optical telescopes like the Hubble Space Telescope because they are also the most obscured by dust.”
Yun also said the discovery has him believing that there are similar galaxies ready to be discovered.
“Now, it could be that there are a whole bunch of them out there and we haven’t been able to see them, but with the LMT we have the power to see them,” he said. “Maybe they’ll start popping out.”
