Astronomers achieve 10 times higher angular resolution of 'monster' galaxy than ever before

Scientists see 'monster' galaxy COSMOS-AzTEC-1 - 12.4 billion light-years away - more closely than ever before

An international team of astronomers have managed to achieve 10 times higher angular resolution with their star-gazing instruments than ever before, enabling them to observe galaxy structural details more closely than ever.

Thanks to an impressive set of tools, the researchers, from Japan, Mexico and the University of Massachusetts Amherst, were able to analyse dynamic properties that have not previously been probed.

The astronomers achieved the breakthrough while studying a "monster galaxy" known as COSMOS-AzTEC-1, 12.4 billion light-years away.

So-called "monster galaxies", or extreme starburst galaxies, are thought to be ancestors of massive galaxies like the Milky Way in today's universe.

These findings should pave the way for a better understanding of the formation and evolution of such galaxies.

"A real surprise is that this galaxy, seen almost 13 billion years ago, has a massive, ordered gas disk that is in regular rotation instead of what we had expected, which would have been some kind of a disordered train wreck that most theoretical studies had predicted," said the study's co-author Min Yun, professor of astronomy at UMass Amherst.

He added that they observed that this gas disk is dynamically unstable now, which means the entire gas disk that makes up this galaxy is fragmenting and undergoing a gigantic episode of starburst, which helps to explain its enormous star formation rate, at more than 1,000 times that of the Milky Way.

These most recent observational discoveries of COSMOS-AzTEC-1 were made possible by the Atacama Large Millimeter/submillimeter Array (ALMA), a telescope and facility operated by an international partnership in Chile.

One of the benefits of the ALMA observations is the ability to see such far-away galaxies with unprecedented resolution.

The researchers used ALMA's high resolution and high sensitivity to observe the COSMOS-AzTEC-1 galaxy, and to obtain a detailed map of the distribution and motion of the gas, to make the highest resolution molecular gas map of a distant monster galaxy ever made.

"We found that there are two distinct large clouds several thousand light-years away from the centre," said Ken-ichi Tadaki, lead author of the study. "In most distant starburst galaxies, stars are actively formed in the centre. So it is surprising to find off-center clouds."