Posted: 07 November, 2008
A new image from the European Southern Observatory (ESO) offers the deepest ground-based ultraviolet image of the Universe ever obtained.
The image contains more than 27 million pixels and reveals a cocktail of brightly coloured and varying shaped galaxies that make up the Chandra Deep Field South (CDF-S). The CDF-S is one of two regions selected as part of the Great Observatories Origins Deep Survey (GOODS), an effort of the worldwide astronomical community that unites the deepest observations from ground- and space-based facilities at all wavelengths from X-ray to radio. Its primary purpose is to provide astronomers with the most sensitive census of the distant Universe to assist in the fundamental study of the formation and evolution of galaxies.
The Chandra Deep Field South observed with ESO’s VIMOS and WFI instruments is the deepest image every taken in the U-band. The image covers a region 14.1 x 21.6 arcminutes. Image: ESO/ Mario Nonino, Piero Rosati and the ESO GOODS Team.
The image combines data obtained from 55 hours of observations with the VIMOS (Visible wide field Imager and Multi-Object Spectrograph) instrument on ESO’s Very Large Telescope (VLT) in the U- and R-bands, as well as data obtained in the B-band with the Wide-Field Imager (WFI) attached to the 2.2 metre Max Planck Gesellschaft/ESO telescope at La Silla. The U-band represents the boundary between visible and ultraviolet light, and in this image is the result of 40 hours of staring at the same region of the sky, resulting in the deepest image ever taken from the ground at this wavelength. At these depths, the sky is almost completely covered by galaxies, each one like our own Milky Way Galaxy, hosting hundreds of billions of stars.
Only a very few stars in this image actually belong to the Milky Way, though, and one can be seen to the left of the second brightest star towards the top of the field of view. It appears as a slightly elongated rainbow because the star moved while the data were being acquired in the different filters over several years.
Such a deep image unveils galaxies a billion times fainter than the unaided eye can see and over a range of colours not directly