The Cosmic Assembly Near-infrared Deep Extragalactic Legacy Survey (CANDELS) is the largest project in the history of the

Hubble Space Telescope The Hubble Space Telescope (HST or Hubble) is a space telescope that was launched into low Earth orbit in 1990 and remains in operation. It was not the Orbiting Solar Observatory, first space telescope, but it is one of the largest and most ...

, with 902 assigned orbits (about 60 continuous days) of observing time. It was carried out between 2010 and 2013 with two cameras on board Hubble – WFC3 and ACS – and aims to explore

galactic evolution In cosmology, the study of galaxy formation and evolution is concerned with the processes that formed a heterogeneous universe from a homogeneous beginning, the formation of the first galaxies, the way galaxies change over time, and the process ...

in the early

Universe The universe is all of space and time and their contents. It comprises all of existence, any fundamental interaction, physical process and physical constant, and therefore all forms of matter and energy, and the structures they form, from s ...

, and the very first seeds of cosmic structure at less than one billion years after the

Big Bang The Big Bang is a physical theory that describes how the universe expanded from an initial state of high density and temperature. Various cosmological models based on the Big Bang concept explain a broad range of phenomena, including th ...

Science goals

CANDELS is designed to document the first third of galactic evolution – on the

redshift In physics, a redshift is an increase in the wavelength, and corresponding decrease in the frequency and photon energy, of electromagnetic radiation (such as light). The opposite change, a decrease in wavelength and increase in frequency and e ...

s from – via deep imaging of more than 250,000 galaxies. Another goal is to find the first

Type Ia A Type Ia supernova (read: "type one-A") is a type of supernova that occurs in binary systems (two stars orbiting one another) in which one of the stars is a white dwarf. The other star can be anything from a giant star to an even smaller white ...

supernova A supernova (: supernovae or supernovas) is a powerful and luminous explosion of a star. A supernova occurs during the last stellar evolution, evolutionary stages of a massive star, or when a white dwarf is triggered into runaway nuclear fusion ...

beyond and establish their accuracy as

standard candle The cosmic distance ladder (also known as the extragalactic distance scale) is the succession of methods by which astronomers determine the distances to celestial objects. A ''direct'' distance measurement of an astronomical object is possible ...

s for

cosmology Cosmology () is a branch of physics and metaphysics dealing with the nature of the universe, the cosmos. The term ''cosmology'' was first used in English in 1656 in Thomas Blount's ''Glossographia'', with the meaning of "a speaking of the wo ...

. Additional "daytime" WFC3/ UV/Vis exposures in the

GOODS In economics, goods are anything that is good, usually in the sense that it provides welfare or utility to someone. Alan V. Deardorff, 2006. ''Terms Of Trade: Glossary of International Economics'', World Scientific. Online version: Deardorffs ...

-N field were conducted to take advantage of its continuous viewing zone opportunity.

Facility and instruments

CANDELS' main instrument is the

Wide Field Camera 3 The Wide Field Camera 3 (WFC3) is the Hubble Space Telescope's last and most technologically advanced instrument to take images in the visible spectrum. It was installed as a replacement for the Wide Field and Planetary Camera 2 during the first ...

, a

near-infrared Infrared (IR; sometimes called infrared light) is electromagnetic radiation (EMR) with wavelengths longer than that of visible light but shorter than microwaves. The infrared spectral band begins with the waves that are just longer than those of ...

camera installed on Hubble in May 2009. WFC3 works in tandem with the visible-light

Advanced Camera for Surveys The Advanced Camera for Surveys (ACS) is a third-generation axial instrument aboard the Hubble Space Telescope (HST). The initial design and scientific capabilities of ACS were defined by a team based at Johns Hopkins University. ACS was assembl ...

, which together gives unprecedented panchromatic coverage of galaxies from optical wavelengths to the near-infrared.

References

External links

CANDELS website
by

University of California Observatories The University of California Observatories (UCO) is a multi-campus astronomical research unit of the University of California, with headquarters on the UC Santa Cruz campus. UCO operates the Lick Observatory on Mount Hamilton, and the technical lab ...

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