VISTA locates earliest giant galaxies

GRONINGEN, Netherlands, Nov. 19 (UPI) -- Researchers have located the oldest giant galaxies in the universe, alive just a billion years after the Big Bang.

The galaxies, some of the oldest ever seen, are the result of an astronomical survey using the Visible and Infrared Survey Telescope for Astronomy, or VISTA. Scientists dubbed the effort the UltraVISTA survey.

Since 2009, the telescope has been scanning a patch of sky the size of four moons, looking for faint galaxies between 0.75 and 2.1 billion years old. They reveal themselves in the form of infrared wavelengths, having traveled hundreds of millions of light-years.

Astronomers combined the VISTA census data with observations made by NASA's Spitzer Space Telescope, which keeps its lenses peeled for even longer, mid-infrared wavelengths.

"We uncovered 574 new massive galaxies -- the largest sample of such hidden galaxies in the early Universe ever assembled," lead researcher Karina Caputi, an astronomer with the Kapteyn Astronomical Institute at the University of Groningen in Holland, said in a press release. "Studying them allows us to answer a simple but important question: when did the first massive galaxies appear?"

By scanning for infrared wavelengths, telescopes can pick up galaxies far, far away that would otherwise be obscured by dust. The census turned up many more giant galaxies than researchers thought they'd find.

Of the the 500-plus giant galaxies, the majority were formed prior to three billion years after the Big Bang. But researchers found no evidence of their presence before about a billion years after the birth of the cosmos, suggesting they arrived on the scene suddenly and quickly populated the universe.

The findings undermine the most popular models of galaxy formation in the early cosmos, which don't predict this many giant galaxies so soon after the Big Bang.

Astronomers say that if even earlier giant galaxies are so dusty VISTA can't see them -- potentially explaining the cutoff at one billion years -- that would complicate things even further. Researchers are now using the European Southern Observatory's 39-meter Extremely Large Telescope to search for these dusty galaxies.

Per usual, the latest findings, published in the Astrophysical Journal, suggest it's again time for students of the early universe to go back to the drawing board. There's more research to be done.