Hubble Reaches the "Undiscovered Country" of Primeval Galaxies
This is the deepest image of the universe ever taken in near-infrared light by NASA's Hubble Space Telescope. The faintest and reddest objects (left inset) in the image are galaxies that correspond to "look-back times" of approximately 12.9 billion years to 13.1 billion years ago. No galaxies have been seen before at such early epochs. These galaxies are much smaller than the Milky Way galaxy and have populations of stars that are intrinsically very blue. This may indicate the galaxies are so primordial that they are deficient in heavier elements, and as a result, are quite free of the dust that reddens light through scattering.
The image was taken with Hubble's newly installed Wide Field Camera 3 (WFC3), which collects light from near-infrared wavelengths and therefore looks even deeper into the universe. The light from very distant galaxies is stretched out of the ultraviolet and visible regions of the spectrum into near-infrared wavelengths by the expansion of the universe.
Hubble's WFC3 took this image in late August 2009 during a total of four days of pointing for 173,000 seconds of exposure time. Infrared light is invisible and therefore does not have colors that can be perceived by the human eye. The colors in the image are assigned comparatively short, medium, and long near-infrared wavelengths (blue, 1.05 microns; green, 1.25 microns; and red, 1.6 microns). The representation is "natural" in that blue objects appear blue and red objects look red. The faintest objects are about one-billionth as bright as can be seen with the naked eye. The galaxy distances are estimated from the infrared colors of their light.
These Hubble observations are trailblazing a path for Hubble's successor, the James Webb Space Telescope (JWST), which will look even farther into the universe than Hubble, at infrared wavelengths. The JWST is planned to be launched in 2014.
The image was created from Hubble data from proposal 11563: G. Illingworth (UCO/Lick Observatory and the University of California, Santa Cruz), R. Bouwens (UCO/Lick Observatory and Leiden University),M. Carollo (Swiss Federal Institute of Technology, Zurich), M. Franx (Leiden University), I. Labbe (Carnegie Institution of Washington), D.Magee (University of California, Santa Cruz), P. Oesch (Swiss Federal Institute of Technology, Zurich), M. Stiavelli (STScI), M. Trenti (University of Colorado, Boulder), and P. van Dokkum (Yale University).