* Astronomy

'Nuisance' data lead to surprising star-birth discovery

When a batch of bright cosmic objects first appeared in maps in 2008 made with data from the South Pole Telescope, astronomers at the University of Chicago's Kavli Institute for Cosmological Physics regarded it only as an unavoidable nuisance.
The light sources interfered with efforts to measure more precisely the cosmic microwave background - the afterglow of the big bang. But the astronomers soon realised that they had made a rare find in South Pole Telescope's large survey of the sky. The spectra of some of the bright objects, which is the rainbow of light they emit, were inconsistent with what astronomers expected from the well-known population of radio galaxies.
Instead they looked like dust-enshrouded, star-forming galaxies. Such galaxies should be easily identified in infrared sky surveys, but there were no known counterparts for what the South Pole Telescope had found. They had to be extremely distant to avoid infrared detection, and therefore extremely luminous. Intrigued, the astronomers performed detailed follow-up imaging of the sources with the new Atacama Large Millimeter Array (ALMA) in Chile's Atacama Desert. These observations show the dust-filled galaxies were bursting with stars much earlier in cosmic history than previously thought.
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