Astronomers have added an ultraviolet perspective to an ultra-deep field view of the universe taken by the Hubble Space Telescope over the past decade.
The new image, released Tuesday, reveals a missing link in galaxy formation, a time when young, massive and hot stars ruled the day.
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"Looking in the ultraviolet we see the youngest stars, and we see them directly when they're not obscured. Seeing where, when and how these stars formed can tell us how galaxies evolved from their very infant stages into the kind of galaxies that we see today," astronomer Harry Tiplitz, with the California Institute of Technology in Pasadena, told reporters at the American Astronomical Society meeting in Boston.
To produce the image, Hubble was repeatedly aimed at the same small slice of the sky it previously studied in infrared and visible light to reveal galaxies dating back to a few hundred million years after the Big Bang.
It took astronomers more than two years to compile the ultraviolet images, which were taken over 841 orbits of Hubble between 2010 and 2012. The Ultra-Deep Field project began in 2003.
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"The ultraviolet (on Hubble's Wide Field Camera 3) is harder to use because the detectors are aging, so there were detector effects we have to worry about," Tiplitz told Discovery News.
"UV is just really hard because there's not a lot of signal. The sky is very dark (in ultraviolet) so we're much more sensitive to the detector effects," he said.
The ultra-deep look in ultraviolet light will be the last for the foreseeable future. The observatory being built to replace Hubble, the James Webb Space Telescope, won't have ultraviolet capability. Instead, it will collect infrared light, in an attempt to learn more about the universe's infancy.