Astronomical survey

An astronomical survey is a general map or image of a region of the sky (or of the whole sky) that lacks a specific observational target. Alternatively, an astronomical survey may comprise a set of images, spectra, or other observations of objects that share a common type or feature. Surveys are often restricted to one band of the electromagnetic spectrum due to instrumental limitations, although multiwavelength surveys can be made by using multiple detectors, each sensitive to a different bandwidth.[1]

Composite image of the GOODS-South field, result of a deep survey using two of the four giant 8.2-metre telescopes composing ESO's Very Large Telescope
Gamma-ray pulsars detected by the Fermi Gamma-ray Space Telescope

Surveys have generally been performed as part of the production of an astronomical catalog. They may also search for transient astronomical events. They often use wide-field astrographs.

Scientific value

Sky surveys, unlike targeted observation of a specific object, allow astronomers to catalog celestial objects and perform statistical analyses on them without complex corrections for selection effects. In some cases, an astronomer interested in a particular object will find that survey images are sufficient to make new telescope time entirely unnecessary.

Surveys also help astronomers choose targets for closer study using larger, more powerful telescopes. If previous observations support a hypothesis, a telescope scheduling committee is more likely to approve new, more detailed observations to test it.

The wide scope of surveys makes them ideal for finding foreground objects that move, such as asteroids and comets. An astronomer can compare existing survey images to current observations to identify changes; this task can even be performed automatically using image analysis software. Besides science, these surveys also detect potentially hazardous objects. Similarly, images of the same object taken by different surveys can be compared to detect transient astronomical events such as variable stars.[2]

List of sky surveys
Spectrum of types of observations of Solar System objects.
The positions in space of just some of the galaxies identified by the VIPERS survey (see Visible Multi Object Spectrograph).[3]
  • Radio
    • Third Cambridge Catalogue of Radio Sources ("3C") - Survey at 159 and 178 MHz published in 1959
    • HIPASS – Radio survey, the first blind HI survey to cover the entire southern sky. 1997–2002
    • Ohio Sky Survey – Over 19,000 radio sources at 1415 MHz. 1965–1973.
    • NVSS – Survey at 1.4 GHz mapping the sky north of −40 deg
    • FIRST – Survey to look for faint radio sources at twenty cms.[11]
    • SUMSS - Survey at 843 MHz, mapping the sky south of -30 deg with similar sensitivity and resolution to the northern NVSS [12]
    • PALFA Survey – On-going 1.4 GHz survey for radio pulsars using the Arecibo Observatory.
    • GALEX Arecibo SDSS Survey GASS[13] designed to measure the neutral hydrogen content of a representative sample of ~1000 massive, galaxies
    • C-BASS – On-going 5 GHz all sky survey to aid in the subtraction of galactic foregrounds from maps of the Cosmic Microwave Background
    • EMU – A large radio continuum survey covering 3/4 of the sky, expected to discover about 70 million galaxies
    • GMRT - The Giant Metrewave Radio Telescope's TGSS ADR mapped the sky at 150 MHz.
    • HTRU – A pulsar and radio transients survey of the northern and southern sky using the Parkes Radio Telescope and the Effelsberg telescope.
  • Gamma-ray
    • Fermi Gamma-ray Space Telescope, formerly referred to as the "Gamma-ray Large Area Space Telescope (GLAST)." 2008–present; the goal for the telescope's lifetime is 10 years.
  • Multi-wavelength surveys
  • Planned

Surveys of the Magellanic Clouds

See also
Wikimedia Commons has media related to Astronomical catalogues and surveys.

References
  1. See, for example, Lacy M, Riley JM, Waldram EM, McMahon RG, Warner PJ (1995). "A radio-optical survey of the North Ecliptic CAP". Monthly Notices of the Royal Astronomical Society. 276 (2): 614–626. Bibcode:1995MNRAS.276..614L. doi:10.1093/mnras/276.2.614.
  2. Gay, Dr. Pamela; Cain, Fraser (26 May 2008). "Episode #90: The Scientific Method". Astronomy Cast (Podcast). Retrieved 16 Dec 2009.
  3. "3D Map of Distant Galaxies Completed – VLT survey shows distribution in space of 90 000 galaxies". www.eso.org. Retrieved 16 December 2016.
  4. Risinger, Nick. "Phototopic Sky Survey". Retrieved 12 May 2011.
  5. Associated Press (12 May 2011). "Amateur Photographer Links 37,000 Pics in Night-Sky Panorama". Fox News. Retrieved 13 May 2011.
  6. "WiggleZ Dark Energy Survey | Home". Wigglez.swin.edu.au. Retrieved 2014-03-03.
  7. "darkenergysurvey.org". darkenergysurvey.org. Retrieved 2014-03-03.
  8. "SLUGGS survey webpage".
  9. "LAMOST survey webpage".
  10. "The Birth of Monsters". Retrieved 14 December 2015.
  11. "The VLA FIRST Survey". Sundog.stsci.edu. 2008-07-21. Retrieved 2014-03-03.
  12. Mauch, T.; Murphy, T.; Buttery, H. J.; Curran, J.; Hunstead, R. W.; Piestrzynski, B.; Robertson, J. G.; Sadler, E. M. (2003). "SUMSS: a wide-field radio imaging survey of the southern sky - II. The source catalogue". Monthly Notices of the Royal Astronomical Society. 342 (4): 1117–1130. arXiv:astro-ph/0303188. Bibcode:2003MNRAS.342.1117M. doi:10.1046/j.1365-8711.2003.06605.x. S2CID 13173524.
  13. "The GALEX Arecibo SDSS Survey". Mpa-garching.mpg.de. Retrieved 2014-03-03.
  14. gama-survey.org
  15. Driver, Simon P.; Norberg, Peder; Baldry, Ivan K.; Bamford, Steven P.; Hopkins, Andrew M.; Liske, Jochen; Loveday, Jon; Peacock, John A.; Hill, D. T.; Kelvin, L. S.; Robotham, A. S. G.; Cross, N. J. G.; Parkinson, H. R.; Prescott, M.; Conselice, C. J.; Dunne, L.; Brough, S.; Jones, H.; Sharp, R. G.; Van Kampen, E.; Oliver, S.; Roseboom, I. G.; Bland-Hawthorn, J.; Croom, S. M.; Ellis, S.; Cameron, E.; Cole, S.; Frenk, C. S.; Couch, W. J.; Graham, A. W.; et al. (2009). "GAMA: towards a physical understanding of galaxy formation". Astronomy & Geophysics. 50 (5): 5.12. arXiv:0910.5123. Bibcode:2009A&G....50e..12D. doi:10.1111/j.1468-4004.2009.50512.x. S2CID 119214918.
  16. "Atlas3D Survey". Astro.physics.ox.ac.uk. Retrieved 2014-03-03.
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