Cosmic Assembly Near-infrared Deep Extragalactic Legacy Survey

CANDELS Research Project Operational


CANDELS is a powerful imaging survey of the distant Universe being carried out with two cameras on board the Hubble Space Telescope.

CANDELS is designed to focus on two critical epochs in cosmic evolution:

  • At "Cosmic Dawn", less than 1 billion years after the Big Bang, the first seeds of cosmic structure began to take shape
  • At "Cosmic High Noon", 2-4 billion years after the Big Bang, galaxies went on a growth splurge as huge gravity-driven rivers of gas flowed into them along the "cosmic web". 

CANDELS fastfacts:

  • CANDELS is the largest project in the history of Hubble, with 902 assigned orbits of observing time. This is the equivalent of four months of Hubble time if executed consecutively, but in practice CANDELS will take three years to complete (2010-2013).
  • The core of CANDELS is the revolutionary near-infrared WFC3 camera, installed on Hubble in May 2009. WFC3 is sensitive to longer, redder wavelengths, which permits it to follow the stretching of lightwaves caused by the expanding Universe. This enables CANDELS to detect and measure objects much farther out in space and nearer to the Big Bang than before. CANDELS also uses the visible-light ACS camera, and together the two cameras give unprecedented panchromatic coverage of galaxies from optical wavelengths to the near-IR.
  • CANDELS will exploit this new lookback power to construct a "cosmic movie" of galaxy evolution that follows the life histories of galaxies from infancy to the present time. This work will cap Hubble's revolutionary series of discoveries on cosmic evolution and bequeath a legacy of precious data to future generations of astronomers.
  • CANDELS will also test the reality of cosmic dark energy by measuring the brightness of a special class of exploding supernovae called Type Ia. By spotting these objects out to farther distances, CANDELS will establish whether these objects are in fact precision "standard candles" for probing the geometry of spacetime. This test is essential to ratify the discovery of dark energy, the most important breakthrough in cosmology since Hubble's discovery of the expanding Universe in 1929.

IPAC's role:

The CANDELS team includes IPAC scientists Harry Teplitz and Ranga Chary, and postdoc Hakim Atek.  Data processing and analysis of the survey's UV component (in GOODS North) is led at IPAC.


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