A long, long time ago, massive, super-bright galaxies known as starburst galaxies were churning out new stars at a frantic pace. Astronomers would like to study their frenetic star-formation physics and compare them to the relatively slow star factories of the modern era, but this is very hard to do. Starburst galaxies are shrouded from our best visible-light telescopes, hiding as they are behind thick curtains of dust. Enter the Atacama Large Millimeter/submillimeter Array.
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The ALMA telescope can see them by looking directly at the dust itself. To ALMA, the starburst galaxies are some of the brightest objects in the sky.
As construction on ALMA has progressed, astronomers have been making a few observations with a few sets of radio-dish pairs, including this latest observation, which was published last week in Nature. Click through our gallery to see a few other ALMA early highlights.
For the starburst galaxy observations, an international team of astronomers used ALMA and the South Pole Telescope, and found they’re even farther away from us than expected. Two of them are the most distant galaxies of their kind that have ever been seen. This means the light that left these galaxies departed when the universe was in its infancy, around 1 billion years old. This is interesting because the galaxies are at least a billion years older than originally thought.
What’s more, ALMA–which is so sensitive it can detect individual molecular signatures–found water in these distant stellar nurseries. The molecules are the most distant observations of water ever made.
One more crazy thing: Astronomers were able to do this in a few _minutes_–observations like these used to take multiple nights. Speed and accuracy are among the many promises of ALMA, the world’s largest ground-based astronomy project.
“We commission as we go, and we’ve tested as we’ve gone along,” explained Phil Jewell, deputy director of the National Radio Astronomy Observatory, an ALMA partner. “We’d like to get the science out…ALMA is such a huge step forward.”
ALMA is an aperture synthesis telescope, which uses pairs of radio antennas looking at the same objects to create a telescope with a huge angular resolution. Each radio dish, eventually 66 in all, forms a pair with every other dish, and their observations are all combined using ALMA’s special supercomputer.
Astronomers celebrated its official inauguration last week in the high, dry desert of Chile, where nearly all the array’s radio dishes are installed and ready to go. I was there with a delegation sponsored by the National Science Foundation and National Radio Astronomy Observatory, and there’s a lot more to share… so stay tuned.
