Chile’s ALMA telescope finds early galaxies in record time

The largest ground-based observatory on earth is astonishing astronomers with the breakneck pace of its discoveries.

The Atacama Large Millimeter/submillimeter Array was inaugurated a little over a month ago, and already its technology has revolutionised the way astronomers conduct study. The telescope is is not even close to operating at full capacity, and yet it is so powerful that in a few hours during one study it made as many discoveries of early galaxies as were made in the decade prior to its opening.

Studying a region of interest previously discovered by the European Southern Observatory (ESO) operated Atacama Pathfinder Experiment telescope (APEX), ALMA went about pinpointing galaxies on the outer reaches of the universe in incredible detail.

Formerly, dust clouds had shrouded these galaxies, though as ALMA detects non-optical light in the millimeter/submillimeter spectrum the telescope could image these galaxies in never before seen detail. The ALMA telescope is also incredibly powerful; operating with just a quarter of its  66 antennae, ALMA imaged the faraway galaxies (in the “Fornax” or “Furnace” region of the Chandra Deep Field South) to an accuracy 200 times that of APEX.

“Astronomers have waited for data like this for over a decade,” Jacqueline Hodge of Germany’s Max-Planck-Institute of Astronomy and lead author of the paper, said. “ALMA is so powerful that it has revolutionised the way that we can observe these galaxies, even though the telescope was not fully completed at the time of the observations.”

Studies of these galaxies have already led to drastic revisions of the astronomical canon. Data suggests that intense star birth – known as “starbursts” – in the regions analyzed occurred 12 billion years ago, just 1.7 billion years after the start of the universe, and a full billion years before previous estimates of the first star formation.

While ALMA boasts some of the most advanced astronomy technology, it has by no means made telescopes like APEX obsolete. Rather, the Atacama-based observatories complement one another.

“APEX can cover a wide area of the sky faster than ALMA, and so it’s ideal for discovering these galaxies. Once we know where to look, we can use ALMA to locate them exactly,” Ian Smail of Durham University and co-author of the new paper, said.

Due to its almost non-existent humidity and clear skies, northern Chile is the world’s premier location for astronomy. Chile is home to almost half the world’s telescope infrastructure, and this is set to increase to over two thirds in the next decade.